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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:
- 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
4.2 ★★★★★
Based on 29 reviews
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Product Reviews
★★★★★ 5
Inexpensive walls.
Color: Grey, Size: 34" - 3 Panel, Color: Grey, Size: 34" - 3 Panel
We had a hot request for a workstation in the warehouse with some privacy.
These have worked great. Easy to assemble. They are lightweight and stable.
This was an inexpensive solution that looks professional. Our client loved it.
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Reviewed in the United States on August 1, 2025
★★★★★ 1
Dont wait! Assemble right away! Just in case you need to return it.
Color: Black, Size: 22" - 4 Panel
Ok, I like the idea of this but the assembly is frustrating. One side lined up perfectly with the holes however, the small bars that connect the screen to base is not lining up. I think it's do the fabric the screen or divider is made of. It's not stretchy. I brought this months ago and just opened it today. I'm upset and don't even think returning it is possible. If the material was a bit longer or stretchy to give a little room to work with this divider would be great. However, I'm not sure what I can use it for since I'm unable to attach it to the bottom. Beware! Don't wait like me. Tip for the manufacturer. Next time invest in Velcro dividers so the fabric can be adjusted with ease. Literally if I take the screen off the frame aligns perfectly. However, it defeats its purpose of privacy. I might buy some material myself and create a more flexible divider. Or I'll buy Velcro myself and attach to the bottom. I don't know yet.
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Reviewed in the United States on December 15, 2025
★★★★★ 5
Great value for price. Cute, lightweight. Could be used anywhere.
Size: 3 Panel, Color: White
Nice, lightweight. Good value for price. It's exactly what I needed for my hallway to keep my cats separate from each other. I used two zip ties to eyescrews in door trim and it opens up perfect to wall. Warm air gets thru and cats can see out/in. But can't get under or over. It's perfect for my use!!!!
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Reviewed in the United States on October 23, 2025
★★★★★ 5
Great seller and really nice items!
Size: 6 Panel, Color: White
These room dividers are really lovely. They are great quality and just perfect for providing privacy in a sunroom while still allowing light in to keep the room sunny. I highly recommend.
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Reviewed in the United States on April 24, 2026
★★★★★ 5
Nice divider!
Size: 4 Panel, Color: White
I use this as a "barrier" to keep my cat out of the guest room. I don't have to close the door anymore because the divider allows light and air through. Adds a nice touch to the decor, as well. Very lightweight and serves its purpose.
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Reviewed in the United States on January 3, 2026