I make my own out of full-length fiberglass fish arrow shafts. Or you can use 36 or 39" fiberglass fence stakes.
Just take a big wad of rubber bands and loop a bunch of them tightly around the two sticks a few inches from one end. They can be flexed out as far as you want them (to go lower) or brought in rather tightly to stay tall. They also help immensely when glassing with binos.
