1. The 4-bay hard drive cage occupies 3-Bay optical drive bays, and it can install 4 x 3.5-inch hard drives. 2. 3.5-inch optical drive bay hard drive expansion rack hard drive cage,for optical drive expansion. 3. for: DIY optical drive bit conversion hard drive. PC chassis, chassis, server chassis, expansion hard drive is a good choice. 4. The product ventilation system is good. Made of high-quality material, , firm and sturdy for us to use. 5. Standard 4 pairs of hard drive plastic guide rails, hard drives can be assembled without tools. Note: 1. If you want to drag the optical drive in a case with 3 optical drive positions, you need to flatten the small iron plate before installing it. 2. Please pay attention to the size of the cage and make sure there is enough room for it in your PC case. 3. HDD Hard Drive Cage only, other accessories demo in the picture is not included! 4. Some PC Chassis may not support this Hard Drive Rack. size:16.6cm x 12.8cm x 14.6cm Material:metal colour:Black+silver gray Package Contents: 2 x hard drive cage 2 set x screws 8 pair x Hard drive rail Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.