The BBC modular buoyancy control is optimal to produce a perfect trim underwater. There are four modules in sizes 1Kg, 2Kg, 3Kg or 4kg. The plastic-clad lead modules can be moved between the bottle back and forth so as to optimally prepare the trim.
An optimal diving location means less force to move in one direction and the diver can concentrate on other activities.
When using single lead modules, they are held in place with a V-bolt between the bottles. But it is also possible to use two lead modules, eg. (1x 1Kg module inside, so directly under the back plate and 1x 2Kg module outside of the bottles to position). Then be screwed with a T-bolt and held in position. All lead module sizes can be combined. Depending on the required amount of lead and position.