SKU: 67323436296

Cooler Master MasterBox Q300L Case, Black, Mini Tower, 2 x USB 3.0 Type-A, Edge-to-Edge Acrylic Transparent Side Panel, Unique Patterned Front & Top Dust Filter, Modular I/O Panel, Vertical or Horizontal Positioning

Sale price$55.58 Regular price$61.75
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Ships within 48 hours · Estimated delivery Jul 14 - Jul 19

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Description

Cooler Master MasterBox Q300L Case, Black, Mini Tower, 2 x USB 3.0 Type-A, Edge-to-Edge Acrylic Transparent Side Panel, Unique Patterned Front & Top Dust Filter, Modular I/O Panel, Vertical or Horizontal PositioningThe MasterBoxQ300L is your straightforward option in the lineup of the brand new MasterBox Q series from Cooler Master. A series that might be small in size but excels in functionality and modularity without compromising on the thermal performance. Although the size wouldnt tell, the MasterBox Q300L supports a standard ATX PSU which we dont see often in the market with this size. Based on the different system setup, the I O panel can be adjusted to

The MasterBoxQ300L is your straightforward option in the lineup of the brand new MasterBox Q-series from Cooler Master. A series that might be small in size but excels in functionality and modularity without compromising on the thermal performance.

Although the size wouldn’t tell, the MasterBox Q300L supports a standard ATX PSU which we don’t see often in the market with this size. Based on the different system setup, the I/O panel can be adjusted to six different locations, three options at each side of the case. You can decide which setup fits your system best.

Due to the cube design of the frame and special pattern design on the magnetic dust filter will make the chassis stand out from the rest. The combination of a practical design and the unique customizable outlook makes the MasterBox Q300L the perfect choice for office and home usage.

Features
- High Flexibility for System Building: The I/O panel can be adjusted to six different locations. On both side of the body you can install the I/O panel at the front, top or bottom.
- Minimized Dimension with ATX PSU Support: Despite the Micro-ATX form factor and the body depth and height of only 370mm x 370mm, the MasterBoxQ300L can accommodate a normal ATX PSU.
- Patterned Dust Filter: Special pattern on the dust filter creates a unique outlook for the chassis.
- Clean Routing Space: Behind the motherboard tray, it offers 28mm wide and spacy room for hidden cable management.
- Excellent Thermal Performance: The open design of the perforated front, top and bottom guarantees excellent thermal performance.
- Edge-to-Edge Acrylic Transparent Side Panel: Show off your build through the full size transparent side panel.
- Vertical and Horizontal Position: The case can be put in vertical and horizontal position.

Model
MasterBox Q300L
MCB-Q300L-KANN-S00

Colour
Black

Materials
Steel
Plastic

Dimensions ( L x W x H )
387 x 230 x 378 mm

Motherboard Support
Micro ATX
Mini-ITX

Expansion Slots
4

Drive Bays
5.25": 0
3.5" HDD: 1
2.5" SSD: 2

I/O Port
2 x USB 3.0
Audio In / Out

Pre-Installed Fans
Front: N/A
Rear: 1 x 120mm

Fan Support
Front: 2 x 120/140mm
Top: 2 x 120mm
Rear: 1 x 120mm
Bottom: 1 x 120mm

Radiator Support
Front: 1 x 120/240mm
Rear: 1 x 120mm

Clearances
CPU Cooler: 157mm
PSU: 160mm
GPU: 360mm

Cable Routing
Behind MB Tray: 28mm

Power Supply Support
Bottom mount
ATX PS2
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 67323436296

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4.3 ★★★★★
Based on 922 reviews
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Product Reviews
J
Jacobson
Fort Morgan, US
★★★★★ 5
Adorable and Well‑Made Outfit for Special Events
Color: Light Blue, Size: 10, Color: Light Blue, Size: 10
Got this suit set for my son and absolutely love it. It comes with everything he needs to look sharp, and I really appreciate that it includes both a tie and a bow tie so we can switch up the style depending on the occasion. The quality is impressive for the price — the fabric feels light and comfortable, and the whole outfit has a polished look without being stiff or uncomfortable. The fit was spot on, and the adjustable waistband is a huge help for getting it just right. My son looked great in it, and it’s definitely something he can wear for more than one event. The little details on the jacket and pants give it a classic, dressed‑up feel that works for weddings, holidays, or any special moment. Overall, it’s a stylish, practical set that makes getting him ready so much easier. Really happy with this purchase.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 1, 2026
C
Crystal
Houston, US
★★★★★ 4
Boys linen fabric suit
Color: Light Green, Size: 16
Boys suit set in a lighter green color. This suit is made with good proportions and seems to fit well. The sizing seems slightly big so maybe size down one size. The fabric does wrinkle easily so be aware that sitting and folding the suit may cause wrinkling. Otherwise it is a very nice suit for a formal occasion. It comes in many good colors.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 29, 2026
A
Atherney Family Farm
Whiting, US
★★★★★ 5
Nice elegant suit for any occasion.
Color: Light Blue, Size: 12, Color: Light Blue, Size: 12
The suit set is very nice, the fabric material is durable and soft. Overall stitching is tight with nice surging of the hems and great construction on the shoulders. Buttons and button wholes are well done. I'm going to iron in the creases on the front of the pants because they weren't folded properly for shipping. The material does hold on to wrinkles so don't be afraid of your iron to get a super sharp look. The color is a soft baby blue that stands out in a crowd of black suits. With the option of an elastic tie or clip on bowtie this is everything you need to make him look presentable for a variety of occasions. My only complaint about this suit kit is the dress shirt is stiff and thin. I found some loose threads that I don't trust to not get played with. I'll probably trade it out for something with a little more cotton. As far as cost goes mid range, but definitely worth the cost. I might consider something with a vest if it's a super formal event, but I'm very happy with how this suit comes together.
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Reviewed in the United States on April 18, 2026
M
Martin V.
Louisville, US
★★★★★ 5
Modern luxury with summer fabric that performs above its price!
Color: Beige, Size: 14, Color: Beige, Size: 14
Wow! My son wore it for Easter Sunday and this suit fits the bill! The linen material is spot on--not too heavy and not too light especially since the weather is warming up now. The jacket is quality made--the design is modern executive, the stitches are strong no flaws to note. The pants are tad bit longer but that's okay, build quality is also great. The white shirt is decent and matches well with the rest of the set. The bow tie and tie itself is a great complimentary to the set, though optional to wear. The whole set just has that quality you would really look for in the price range you would want to pay. Overall, best value for for the, wear right outside the bag, maybe a light ironing otherwise it's perfect! I highly recommend it, no complaints here very happy with this suit!
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Reviewed in the United States on April 5, 2026
A
Ariel B.
Houston, US
★★★★★ 4
Heavy linen character, but a beautifully tailored suit!
Color: Beige, Size: 4, Color: Beige, Size: 4
This is a really nice linen suit! The jacket is beautifully made and well-tailored, with a fun speckled texture that has lots of pretty color variation (we ordered the beige). When I placed it side by side with a similar linen suit from another brand, the difference in the linen texture was really noticeable — this had a much stronger linen character that stands out! It has three useful pockets on the outside of the jacket, which is great for little hands. The only downside is that one of the inside pockets is just for show (faux), which was a bit surprising and somewhat disappointing for my little guy. The pants have pockets too, but they aren’t very deep — perfect for small treasures, but not much more. The pants are made from a lighter, thinner single-layer linen compared to the fully lined, double-layer jacket, which makes sense for comfort and easy movement. The pants didn’t come with a front crease ironed in, so you’ll want to press one yourself. The linen did pick up some creases from being folded in the package, but it doesn’t seem quite as wrinkly as some other linen fabrics I’ve tried. Still, like most linen clothes, especially for boys, the pants will need occasional ironing to keep them looking neat and crisp, especially after a day of play and general wear. The structured, lined jacket stays looking smoother and more put-together with less effort. It also came with a bow tie, a neck tie, and a tuxedo-style white shirt as extras. The ties aren’t great quality — they’d work fine for quick photos but probably won’t hold up to much actual wear. The formal white shirt feels a bit funny paired with the casual linen suit, but I don’t mind at all. We already have white shirts that we prefer, so we’ll use those instead. For us, the extras are really just bonus items we won’t plan on using. Overall, it’s a handsome little suit that’s perfect for special occasions like weddings, family photos, or holiday events. My kid looked adorable in it! The stronger linen texture on the jacket gives it a premium feel that I really like. Just be ready for a bit of extra care with the pants to keep everything sharp.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 8, 2026

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