My arms aren't big, just measured and 10 inch circumference at the elbow crease level around the funny bone, 4 inch diameter. I can just get my arm in and out if wet, easier in than out of the fermentasaurus. That looks identical to the 9.2 impact + conical unitank ( the other impacts have the same size opening).
You'd need a long arm to get to the bottom of the bigger impact though. I've seen the sledge and the opening is far too small for your arm even a childs arm.
I use a CIP ball on a pond pump and PBW. I also picked up this little water bottle cleaner in a japanese store very cheap works great if it does need a rub.
Lighter is for scale no other relevance. I love that I can get bright beer with a closed transfer carbed into the keg with these unitanks. Great for yeast harvest as well. Do not try and dry hop up thru the bottle on the bottom it doesn't work well at all especially if under pressure and using leaf hops.
Use magnets and bags just much more user friendly.
THis picture after dry hopping was over and I lifted the hops out, lets them drain and stops over expression / bad flavour.
You do need a good sized fridge as well.
