The UltraLight Control System Digital tray for Medium Size Ikelite Olympus Pen Housings for housings with two screw holes for attaching on the bottom of Housings for this tray Ikelite small and medium with female threads on the bottom. The tray is also suitable for olympus Pen housing, PT-EP01, PT-E05, PT-E06, Fisheye Fix housings, RecSea housings with two threaded holes in the housing. If your housing only has one threaded hole then you need the TR-D tray. This tray uses the AC-H handle in the left slot allowing you to adjust it left or right to place your hand in the best place. Uses the TR-DUPL as the upgrade piece to make it a double tray and adding another AC-H handle. Comes with bolts for Ikelite (12/24) and 1/4-20 T-knobs for all other housings.