The bosch grl250hv professional rotation laser is easy to operate thanks to the one button per function system it is easy to set up in both horizontal and vertical modes thanks to the automatic self levelling operation of 8 plusmn 5deg there is a shock warning function that prevents levelling errors in the event of shocks or vibrations affecting the unit this function can also be turned off this unit comes complete with alkaline batteries 2 x 15v lr 20 d a moulded carrying case and