Replacement for this nylon drawer piece

I had trouble posting to your website. I'm looking to replace small nylon piece that attaches to the back end of a metal guide that is attached to the bottom of a drawer. The guide runs down the center of the bottom of the drawer. The nylon piece interlocks with another metal guide attached to the frame of the cabinet.

The attached photos show the piece I'm trying to replace.

I'd appreciate any help you may be able to give me.
Thank you.
Mark