RPB Safety 17-817 T-Link Clear-Vision Cassette Lens he RPB Safety 17-817 T-Link Clear-Vision Cassette Lens (7 Layer Set) is a replacement part for T-Link Respirator. RPB Safety's unique cassette tear-off lens system designed for the T-Link features one outer lens fused with seven tear off lenses, preventing dust from getting in between the lenses.This product contains 7 disposable lenses that cover the respirator visor. Only for use with the RPB Safety T-Link respirator