I have only used elbows that come with with hoppers, so not any related products.
Spyder Compact, Evolution hopper, Dye X-el 14'' barrel, fruit of the loom boxers.
Mine cracked in like a day of use and the screws got lost really fast.
It was allright for the few games that the thing lasted, after it cracked my hopper kept on falling off and stuff. Its not worth getting one i dont think, just use the elbows that come with that hopper you buy. I ended up duct taping my hooper directly on to my gun by the end of the day because of this elbow.