Spring-Loaded Guide Roller with Nails

Spring loaded
7/8 inch dia. nylon wheel
Top mount
Self adjusting
Fits 1 inch to 1-3/8 inch thick bi-fold doors up to 30 lbs each
Sold in pairs, priced in pairs

Base Diameter: 3/8-inch
Diameter: 3/8-inch
Material: Nylon
Type: Pin Guide Pin

This product is similar to or the same as the following part numbers in these brands:
Prime-Line Products: N 6614
SlideCo: 162984