The BBC (ballast & buoyancy control) Ballast and buoyancy control systemis a plastic-coatedlead systemwhich is suitable for double cylinders with narrow (double cylinders 7L - 20L or double cylinders with wide clamp spacing 7L and 8.5L.
 
TheModules 1kg - 4kgare placed between the bottles with a bolt. This can be done directly between the backplate and diving tanks1Kg module with a V boltbe screwed. 
The great advantage ofBBC lead systemis that the modules can be moved up or down between the scuba tanks. This greatly improves the diver's dive attitude ( Trim ).
 
Depending on therequired amount of weight of the diverthe possible combinations are very large.
 
1kg amount of lead- 1Kg lead module + V bolt
2kg amount of lead- 2Kg lead module + V bolt or 2x 1Kg lead module + T bolt
3kg amount of lead- 3Kg lead module + V bolt or 1x 1Kg lead module + 1x 2Kg lead module + T bolt
4kg amount of lead- 1Kg lead module + 3Kg lead module + T bolt
 
From a lead quantity of 4 kg, the BBC lead system should be combined with a P Weight  2Kg - 5.5 kg. 
 
5Kg lead quantity - 1Kg lead module + 4Kg lead module + T bolt
6Kg amount of lead - 2x 1Kg lead module +2x 2Kg lead module + 2x T bolts 
8Kg lead quantity - 2x 1Kg lead module + 2x 3Kg lead module + 2x T bolts