Siddhagiri Metals & Tubes is India's largest manufacturer of stainless steel fasteners. PTFE and Teflon are two more low-cost coating compounds that could be used to coat self-drilling stainless steel fasteners. Visit the website for additional information and to receive the best price. www.siddhagirimetal.com/astm-a193-stainless-steel-nut-bolts-fasteners.html