This is a drawer guide and glide set constructed from mold injected brown plastic. Typically this set can be used with a majority of furniture drawer systems. The saddles offer less resistance on the drawer being pulled out or pushed in making this set perfect for your dressers, hutches and night stand drawers. Opening for metal track on the large piece is 15/16 in. x 3/32 in. make sure to measure your track before ordering. All the necessary mounting hardware is included for a quick and easy installation.