Stainless steel U-bolts for NRS LoPro™ Frame Fittings and other frame accessories. Curve of the U-bolt is flattened, or coined, to reduce impact on boat material. It's shaped to fit our 1 5/8 diameter frame pipe. The 2 1/8 deep Standard size U-bolt is used with LoPro Frame Fittings. We use the longer 2 5/8 deep Oversized U-bolt with our Raft and Cataraft Anchor Systems, Lower Cat Rail Spreader Bars and Cataraft Frame Aluminum Floors. Folks building their own custom frames may also find use for these U-bolts. Tips of threaded shanks are rounded, eliminating sharp edges. Each U-bolt comes with two 1/2 zinc-coated nylon locknuts and two zinc-coated flat washers. Bolt thread is 5/16-18. Category: Frame Parts Weight: Single bolt with nuts & washers is 0.1 lbs. Included Components: 1 - U-bolt with nuts and washers Notes: Bolt thread is 5/16-18 Rounded bolt tips Size A B Standard 2 1/8 1 5/8 Oversized 2 5/8 1 5/8