Our Range of Metric U bolts are manufactured from marine grade 316 stainless steel with a plate that sits underneath plastic nuts that are threaded onto the bars. We manufacture a range of U bolts from M4 bar to M12 in varying thread lengths. All U bolts come with washers and nuts. A dimension between the centres of the upright bars B dimension height from plate to top of U C dimension length of thread under the plate M6x50 M5x50