1/4" x 4" x 6" Universal  Aluminum Plates  For 2" Mast to 2" boom or connecting H frame for Antenna Yagi  System or for vertical extend 2" mast to 2" mast. Comes with 4 yellow zinc plated U-bolts and saddles.  U-Bolts: This is professional grade series. This series provides high strength steel 5/16” U-bolt with a patented ribbed and notched 13 gauge double edge saddle and hex nuts. This unique clamp offers a lightweight alternative with outstanding strength and seal-ability. Mast Plates keep your Yagi stable and properly secured on the mast.