Copper-Free Aluminum (Less Than 4/10 of 1%). Natural Finish. 300 Series Stainless Steel Screws | Support Grips | Used With Starter Sizes 00-0 (Series c), Sizes 1-2 (Series b), Iec Sizes a-F (Series c), Iec Sizes G-K (Series b) | Used With Type Br LoadcentersSouthern Tier Electric Supply