A cast aluminum base for mounting air terminals to vertical pipes or railings where conductor is not required up to 6-3/4 in, (17.15 cm) OD. Stainless steel U-bolt, nuts and washers. 8 x 8-1/2 x 1-1/2 in. (20.3 x 21.6 x 3.8 cm); approximately 20 oz. (567 g). Use suffix 1/2 and 5/8 inch to denote air terminal thread size.