Aluminum sliding glass door.

You are showing the inside part of a roller assembly, similar to our 81-004. You will need to remove the sliding patio door. Start by carefully laying it down on saw horses or a large table. Unscrew the two bottom frame until it screws out. With a block of wood and hammer carefully knock off the bottom rail from the glass. Looking at the rail where the glass fits into you will see a screw like the 33-013 that is holding the top roller assembly to the frame. Remove the screw and slide out the housing and match it to our patio glass door rollers we offer here.