The DB4+ (1st stage of the XL4+ set) is an overbalanced membrane-controlled first stage with extreme cold water properties: regardless of the depth and pressure of the tank, the breathing resistance remains the same. For more power at depth.
It has a dry transfer chamber, which reduces the risk of icing and keeps the mechanics clean and dry.
It is encapsulated, without rotating distributor block, has 4 medium-pressure outlets (3/8 ") and 2 high-pressure outlets (7/16"). DIN connection (suitable for bottle pressures 200 and 300bar).
Especially the DB4+ is also used in technical diving!