KDS is a special seal ring for hinged joints. It is suitable to be used for sealing directly against threads. Require no special machining or style of bolt, screw or thread. These are self centering, non-directional and low cost; KDS provide considerable savings because they make possibility of  the use of low standard fasteners and full threaded fittings. Easy to assemble ,No special tools or skill is needed. 
Huayi sealing Factory are able to offer high quality Standard Size KDS & Coustmer made KDS OEM Service.