The Apeks US4 first stage uses a balanced diaphragm design like the rest of the apeks range but it is not fitted with a environmental seal making the first stage smaller and lighter but suitable for warm water above 10 degrees C only.
The US4 is fitted with four low pressure ports and one high pressure port which makes it ideal for travelling divers that want the reliability and performace that Apeks regulators offer but won't be using it in cold water.
- Unsealed system for warm water
- No turret
- Four low pressure ports 3/8" UNF
- One high pressure port 7/16" UNF