Product Highlights
• A packet of 2 pieces
• For universal use 
• With 1/4"-20 & 3/8"-16 threaded holes 
• Minimum opening diameter :3mm
• Maximum opening diameter: 42mm
• Material: aluminum, plastic & metal

Product Description: 
• It provides 8 1/4"-20 thread holes and one 3/8"-16 thread hole.
• Attaches easily to desks, carts, benches, worktables, posts, etc.
• C-clamp jaws expand from 3mm to 42mm wide.