Prime-Line 7/8 in. D X 0.38 in. L Plastic/Steel Shower Door Roller 2 pk

This is a 7/8 inch tub & shower door nylon ball bearing roller with an oval edged wheel. It has a threaded hex head hub that uses an 8-32 x 3/8 inch long Phillips binder head machine screw to fasten it to the door bracket. Used on many different tub and shower top roller systems. See M 6000 for 3/4 inch roller.