The AT20 regulator is no longer available with the Unsealed Swivel Turret (UST) 1st stage. This is now supplied with the US4 1st stage. The AT20/US4 regulator has been designed for warm water diving. Just because it is warm water equipment does not mean it is of low quality. The AT20/US4 is a very good breathing regulator featuring our venturi control and it is also balanced.
