Eisco labs 3.875" Diameter Closed ring with Boss head clamp.

Plated mild steel with 5/16" diameter stem, with open boss head fitted with thumb-screw to accept rods from 5/16" to 5/8" mm dia. Extension distance from boss head to ring is approx. 7/8", Outside diameter of ring 3 5/8" Clamp from Boss head center line measures 5/8" to edge of closed ring.