A cast aluminum base for mounting air terminals to the top of horizontal pipes or railings where conductor is not required up to 4-1/2 in. (11.43 cm) OD. Stainless steel U-bolt, nuts and washers. 6-1/4 x 6-1/2 x 1-1/2 in. (15.9 x 16.5 x 3.8 cm); approximately 12.4 oz. (351 g). Use suffix 1/2 and 5/8 inch to denote air terminal thread size.