... (mm) 1/4" x 1/4"6.4mm x 6.4mm22,23,24 3/8" x 3/8"10.6mm x 10.6mm19,20 ... ,21,22 1/2" x 1/2"12.7mm x 12.7mm16,17 ... ,23 5/8" x 5/8"16mm x 16mm18,19,20,21, 3/4" x 3/4"19.1mm x 19.1mm16,17,18 ... ,19,20,21 1" x 1/2"25.4mm x 12.7mm16,17,18,19,20,21 1-1 ... ,16,17,18,19 1" x 2"25.4mm x 50.8mm14,15,16 2" x 2"50.8mm x 50.8mm12,13,14,15,16 Technical ...