Clemco couplings are made from top grade brass and aluminum materials in addition to super tough nylon. Universal quarter-turn locking lucks permit interconnection of different size hose couplings from 1/2" to 1-1/4" if desired. Coupling shanks are extra long for added support and holding strength. Screw holes are countersunk to accept No. 10 x 1/2" wood screws. (NOTE: Improper screw size could result in puncture of blast hose tube.)