The distance-regulating means (6, 7, 16) is provided for lowering the net bag (2) with the top net (3) when an external environmental effect is threatening the fish in the rearing unit.

Each flotation unit comprises an individual supply hose, an inflatable bladder, a relief valve, a diffusing manifold, bottom mesh, top mesh, and buoyant growth medium.

It is desirable to have a removable top net (37) to prevent tennis balls from traveling to other lanes.

The tops of the tanks are open to the atmosphere but are protected from predators via a thick mesh top net.

The top net (3) is sewn to the jumping fence of the rearing unit so that with the net bag (2) it forms a closed unit, from which unit the fish can not escape.

The device comprises a frame (4) and a top net (3) which has a shape that is adapted to the floating ring (9).

Additionally, the D-19 had a D-28 style rosette, and D-21 style top purfling.

However, the larger root radius of the Unified thread proved to be advantageous over the DIN metric profile.

Based on the HCU-6/E air cargo Master Pallet, additional components include the HCU-7/E side net, the HCU-15/C top net, and the CGU-1/B Device or cargo strap.