Related Post: 20 X 3 1 2 20 3 X 25 1 1 4 20 X 3 1 2 Bolt 1 4 20 X 3 1 2 7 16 20 X 3 1 2 1 4 20 X 3 1 2 Machine Screw 1 4 20 X 3 1 2 Carriage Bolt 20 3 X 1 20 20 21 X 1 3 4 X 3 1 2x 5 )= 20