Extension Piece Application : Brass Finish and Chrome Plating Light / Medium / Heavy weight. Size / Size : 1/2″ x 5 mm. : 1/2″ x 10 mm. : 1/2″ x 15 mm. : 1/2″ x 20 mm. : 1/2″ x 25 mm. : 1/2″ x 30 mm. : 1/2″ x 40 mm. : 1/2″ x 50mm.