S-1: 5/32" x 5/16" S-2: 1/4" x 5/16" S-3: 1/4" x 3/8" S-4: 1/4" x 1/4" S-5: 5/16" x 5/16" S-6: 5/16 x 3/8" S-7: 3/8" x 3/8" S-8: 3/8" x 1/2"