yes the contacts, breakers and terminal blocks all clip in... and a relay if you are going that route. I use a relay to make sure the elements are off before the control panel will start. I recommend you check out the parts at ebrewsupply . com. The price on the 63amp contactor is almost worth going that route alone. if you are going to use four 30 or 25amp breakers for you elements then you can get them on ebay near the same price. the breakers that ebrewsupply has are better quality then you get on ebay. Did you see the inside of my panel, all DIN RAIL.