: I've heard of people just cutting pieces of PVC pipe to make the same thing

In fact they are the same material. The maker posted on one of the forums (don't remember if it was this one). They are made so that they can be used with one hand, as opposed to the pvc home made ones which can be cumbersome when what one really needs is THREE hands.

Never tried them, but if nothing else, I admire the chap's entrepreneurial verve.

Paul M