Not a 100% vitally necessary item but one which has made some jobs much easier, cleaner and far more efficient. There is a knack to making best use of it though. Use preheated water and put smaller items in smaller container your cleaning solution and that way you can use plain water in the main tank and not contaminate the tank with grease, oil etc. Using small containers does NOT affect the cleaning action. Cracking piece of kit if used correctly and at price that doesn't break the bank. Just make sure you buy big enough for all your uses otherwise buyer regret slips in. I judged mine just about spot on; big enough to clean my CPAP water container.