A small part of the backplate is visible behind the necks of the pressure tanks. All parts of the apparatus, including the attachment straps, are attached to the backplate. The backplate continues downward with the base, which transfers part of the apparatus’s weight to the diver’s lower back, protects the tank valves against damage and serves as a pedestal for standing the apparatus on the ground. The upper edge of the base fits into grooves in the bottom of the air-mass treatment unit.
Equipment seen on the back of the CCR Liberty includes the noticeable ballast pouches attached to the tanks. These pouches feature downward-hanging red “rip cords” for emergency jettisoning of the ballast, which is to be taken into consideration in the case of flooding of the whole apparatus or difficulties on the surface.
Firmly attached to the backplate are the first stages of the regulators (reduction valves), which reduce the high pressure of the gas from the tanks (up to 300 bars) to medium pressure (overpressure of 8.5 bars as compared with the ambient pressure), which is then distributed by the hoses to the necessary places in the apparatus. Thanks to the firm attachment of the first stages to the backplate, the regulators also serve as one of the attachment points of the pressure tanks, which are affixed to the backplate with DIN G 5/8̋ʺ (diluent) and M26×2 (oxygen) screws. The straps, which are hidden behind the upper part of the ballast pouches, serve as the other attachment point of the tanks.
The buoyancy compensator (BCD), which is structurally designed as a “wing” and is visible on both sides, contributes to the outline of the overall rear view of the Liberty.
It is worth mentioning the horizontal strap encircling the lower part of the air-mass treatment unit. Its interesting feature consists in the fact that the unit is not attached using that strap, which serves only as a safeguard and for securing the lower part of the ballast pouches. The actual means of attaching the air-mass treatment unit is described below.