{HEAD ~ a friction element} including {TAIL ~ the friction surface}, said friction element being removably supported on said base, whereby said friction element can be interchanged with other friction elements for providing respective different friction surfaces, and said base includes a recess for removably holding said friction element 
including
{ HEAD ~ a friction element } including { TAIL ~ the friction surface } , said friction element being removably supported on said base , whereby said friction element can be interchanged with other friction elements for providing respective different friction surfaces , and said base includes a recess for removably holding said friction element
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH