Assuming that you're talking about the small, cylindrical unit with the knurled, screw-in allen wrench fitting, Fenton Sandlin in Alba, TX 'did' make them. Whether he still does, I don't know.
I think that Don Weathersby -- longgun on here -- might either be making them or selling some that remain from earlier.
If Don doesn't respond here, pm me and I'll get you contact information for Fenton.