BOSCH GBH 18 V-20 18v 3 function hammer - SDS plus 
2 x 5.0Ah Li-ion batteries and charger
Variable speed
Max in concrete: 20mm
L-BOXX

An introduction to hammers: Hammers combine a pulsing pressure action, or "hammer blow", with the rotating of a bit to break through denser materials. The SDS system was originally invented in 1975 by Bosch and translates as "insert, twist, fits". The slots on SDS bits enable the back-and-forth hammer blow action whilst still rotating. The drill bit is locked but at the same time can rotate. This system transfers the energy that the hammer builds up internally through to the tip of the drill bit without damaging the chuck.