A fastener such as a Nut and bolt, Or washer has a series of spikes or teeth on a bearing surface which is engageable with a workpiece. The spikes or teeth can grip the workpiece to lock the fastener against relative rotation with respect to the workpiece.
website:https://www.jhmindustry.com/
Shanghai Jian & Mei Industry and Trade Co., Ltd. is the company which manufacture and export fasteners and metal hardware, founded in 2006, with import-export authority. Now, 80% products export to all over the world and 20% sell in domestic market.