Like the ego batteries, currently using 2 ego-C 1000 upgrades. Last all day on high voltage mode and are shorter than the twist. Fits great in my pocket for the.work day vaping. Dropped many times and keep working. I'm luckey to have a local cignot were I get genuine joytech products, snapped my setup more than once in my pocket sleeping on it and they fix it for free. Many 650 egos are in the battery rotation too.
Ego tanks are ok if they work for you, used the type B tanks for a while till I came on this site and order some T3'S
and mini nova tanks and will never go back to ego arty system.