The Life-Pak 1 was manufactured by the Physio-Control Corporation in the and was designed in the 60's for in-hospital use and did not feature an EKG monitor scope. This device actually pre-dated the Life-Pak 33

The Life-Pak 2 was introduced in 1972 and featured a larger EKG scope that the Life-Pak 33. The Life-Pak 3, introduced in 1973, appeared almost identical except for the fact that you could "freeze" the EKG rhythm on the scope with the Life-Pak 3 model.