Purlin Clip – Mounting Base – and Cable Tie for Cable Bundle, 1.5-4mm, Mounting Bases and Cable Ties are made of Polyamide 6.6, Cable Tie is 7.6mm X 370mm, Zinc silver colored sacrificial coating (Z600+), waterproof topcoat, for use in indoor and outdoor humid and mildly corrosive environments. Coating is completely chromium free.