I have two GT Power System, one is a plain lorry sound and lights and one that I think is advertised as the Truck Container Sound and Light system. personally I wouldn't buy the second one if it was the only unit on the market. Didn't work, went back to supplier who agreed it didn't work, they sent it to Perkins who said it did work, when it still didn't, and then had the nerve to try and charge me for the postage......no chance. I did get it working by joining two outputs together but never did get the vibration motor working. IMHO biggest waste of money for that particular unit.Perkins did try and blame me for using the wrong size battery and overcooking it, until I pointed out that their specification stated the voltage of the battery required and they even supplied the lead (lipo) for same. i.e.can't connect a two cell to a three cell plug!!!!