These sew-in carriers are used in Airstreams from 1973 forward. They are designed to fit a channel 1/4″ wide. The slider width is just a hair under 1/4″. Each slider has a slot in it where a piece of elastic can be slipped through.
Natural Nylon Sew In Tailslides Tail Slides Curtain Carriers Tracks 14 PCS
DMSE Nylon tab that is sewn directly to curtain. Also available attached to webbing as part 3089.