Application: To pave and break concrate foundation installing engenering to break other hard things. Instruction: The paving breaker model SL87C is tools with compressed air as its power.The compressed air is distributed alternatively through the distributing vaive into either end of the cylinder assembiy so that the hammer inside is made to carry on a reciiprocal motion which impacts the shank of the steel chisel by the tappet drives the chisel into the concrate foundation and makes them split into huge pieces.