Screw-on regs

[bjyourk]

Heres some good fodder for all you professionals(NOOOOOB!).....Don't they make an adjustable reg. that your bottle screws into, and in return, screws into your ASA? Are they as effective as an adjustable tank reg.?

[longi]

Nitro Duck made them, but i think they've gone bust. I heard pretty good things about them but other than that no one make them.