Designed to fasten luminaires to a tube or pipe with an outside diameter 1-1/2” to 2-1/2” (35mm-65mm). This iron casting clamp is durable to hold a payload up to 220lbs (100kgs). Comes with 3-1/2” steel long shaft and 1/2”-13 bolt & washer. Main body has a bonding position to safety wire to anchor.