Just to let you know....
MRC is re-issueing the TECH 4 600 powerpack item # AH600- starter set pack 50 watts, whistle/horn button
MRC is coming out with two brand new A.C. Power Packs:
# 0001311 - 100 watts, bell and whistle/horn button, available May 2013
# 0001321 - 150 watts, bell and whistle/horn button, LCD voltage/amp meter, available summer 2013