This single-arm heavy duty boom comes with a solid steel pillar and a long solid aluminum arm. The diameter of the holder ring is 3" (76mm). It is an ideal stand for gemologists, collectors, engravers and engineers in industries. This stand is brand new in factory sealed box. Features & Specifications: 3" (76mm) Holder Ring 26" Overall Length 20" Single Arm 16" High Pillar 10" x 10" x 3/4" Solid Cast Steel Base Shipping Weight: 45 lbs