Polyurethane jaw coupling inserts/spiders/dampers also called PU spiders or urethane coupling spiders are made of excellent quality PU from famous companies and with varieties of designs,colors and sizes including series of GR,GS,MT,T,L,R,NM,MH,HRC,YOX etc.And also can be customized according to buyers' special requirements.They are the key parts to jaw type flexible couplings.