This caddy system for 3.5" hard disks features This is designed to fit into an existing enclosure, hence the non standard size. This will not fit into a 5.25" bay! Video of it working http://youtu.be/EnGbpf_GoWUprint the parts. shell should be sliced at 0.2mm with single wall and 10% infill everything else should be printed 0.2mm double wall 25% infill. no supports required apart from ont he SATA backplane. the lever is the hardest part to attach. You will need a nice long screw that has a small head. The head should not protrude over the top of the inner caddy tray. it should be long enough to ready through to the bottom. Again it should not stick out of the bottom. Once you have put the parts together, use superglue to attach the backplane of your choice. Currently there is only SATA. Once glue is set, put a hard disk in the caddy, and push it into the shell. Put the SATA connectors into the harddisk, and apply glue around the back SATA plate. Wait for it to set. DO NOT glue your had disk in the caddy!