Apeks has developed unique 1st stages specifically for use on a twinset. They have launched the new TEK3 1st stage regulators designed for use with twin cylinder configuration. The system benefits from streamlined hoses with little chance of accidental snagging and also improved ease of access to cylinder valves. Each 1st stage has 3 medium pressure ports and one high pressure port. They are balanced, cold water compatible and extremely robust. TEK3 looks great too.