Install the HDD in correct orientation , Otherwise the Caddy will bend. Only suited for 2.5" SSD  OR NOTEBOOK HDD,  It's thick must less than 10mm ! Hard Drive is NOT Included  !   Only shown for product mounting purpose ! External Diameter :  133mm x 102mm x15mm  ( Length , width , Height )  . It's shorter in length and height  than 3.5" HDD. Width is the same as 3.5" HDD .  Please refer to the pictures