Prime-Line N 6720 Zinc Closet Door Roller - Smooth Sliding Replacement Wheel for Bifold, Sliding, and Bypass Doors - Perfect for Home, Office, and Closet Organization

Our house was built in the early 60's and all the original sliding closet doors use this kind of roller, two per door. (Look at yours before you buy this; the screw hole arrangement is pretty distinctive.) The original plastic wheels were white and these new ones vary from light brown to dark brown. I assume that the new ones are made from recycled plastic.If you have squeaky rollers, your choices are to buy new ones or lubricate the old ones. Since the wheel is plastic on a metal shaft, you have to use something that isn't oily and won't soften the plastic. Prime-Line has a recommended spray-on lubricant, RZ 50, that dries completely, and I can verify that it works for at least the short term. (Amazon currently sells it.) You do have to take the doors off the overhead track to expose the plastic wheels.Note: Each of these packages comes with two rollers.