Plumbers felt is a pressure sensitive adhesive backed felt that is used primarily to line pipe hangers. Other uses are to line pipe clamps and dampens vibration to prevent noise. It comes in different thicknesses which are 1/8", 3/16", and 1/4". The Most popular Felt is 3/16" x 2"x 25'. Rolls vary in length depending on the felt thickness. Custom widths and lengths can be done.