Once available only for commercial use, these tiny, heavy-duty swivels from SPRO provide tremendous strength and durability for their size. The black Heavy Swivels come in sizes 3 (150 lb. test), 4 (200 lb. test); 5 (280 lb. test); 6 (340 lb. test); 7 (410 lb. test); and 8 (570 lb. test). Great for keen-eyed fish and wind-on leaders. SPRO Corp., Kennesaw, GA; (770) 919-1722; http://www.spro.com.