Choose the model Brass extension male/female 3/8" x 20 mm Brass extension male/female 3/8" x 40 mm Brass extension male/female 1/2" x 20 mm Brass extension male/female 1/2" x 40 mm Brass extension male/female 3/4" x 20 mm Brass extension male/female 3/4" x 40 mm Brass extension male/female 1" x 20 mm Brass extension male/female 1" x 40 mm