I think the Bristan ones are plastic, but they are smaller projection from the wall than the others , which can get you out of trouble with some valves.
I too think the swirl ones are one of the best, also few quid cheaper, I tend to buy half a dozen of these at a time as our merchants charge nearly double for inferior ones, imo.
I too think the swirl ones are one of the best, also few quid cheaper, I tend to buy half a dozen of these at a time as our merchants charge nearly double for inferior ones, imo.