i paid around £23.00 inc vat for a 28mm compression stoptap just to isolate a cattle drinker fed from the mains by a 3/4 black plastic pipe. liners for the black pipe are inc in this price. the make of the stoptap is kx. i checked the price of a brand called comap and its around a tenner. why was my stoptap so expensive? is kx a superbrand or is there designer brands even in plumbing. could i have used sumthing else to isolate the drinker, maybe a 28mm isolation valve or reduced the pipe to suit a 15mm stoptap. this thing looks massive hanging on a pipe. much appreciated.