The Classic Packs are well known for their durability and simple effective design. This is like most of the 400ws Packs we've made for all these years. The two jacks are the normal Lumedyne head plug. If both are used then the power will be split between the two heads.
The Pack has two switches that control the power level. With the Lumedyne Heads, you would select the power with the switches on top of the Pack. The sync connection and test fire button are on the Head.
The Pack can use AC or battery power and is compatible with the Boosters and High Speed Modules and all generations of Flash Heads. Shoulder Strap included.