the first clamping unit being adapted to hold the sheet adjacent an upper edge thereof and the second clamping unit being adapted to hold the sheet adjacent a lower edge thereof the system is used in training exercises for emergency measures personnel who need to be able to break automotive glass to gain entrance to a vehicle application_number US 60471406 A description referring to the drawings there is shown in fig1 the clamping system 10 according to a preferred embodiment of the invention in use on a vehicle 1 the clamping system 10 comprises an upper clamping unit 12 adapted to engage the upper portion of the doorframe 2 of the vehicle 1 and a lower clamping unit 14 adapted to be secured to the outer surface of the door 3 of the vehicle 1 below the lower portion of the window opening the clamping system 10 serves to hold a sheet w of automotive window glass in place over where the original window is located in the vehicle door therefore the glass sheet w can easily be replaced multiple times during training exercises without damaging the original vehicle windows the upper or first clamping unit 12 as shown in fig2 comprises first inner and second outer clamping bars 12 a 12 b which cooperate in order to engage an upper portion w of the sheet w of automotive window glass the first clamping bar 12.