I purchased the 650mah Ego C Twist Battery the day they came out and was a little surprised how quickly it needed to be charged (running at 4v.) I was getting about 4hrs per charge But now I have the 1000mah big difference, It's a little long[4.5 inches] but still perfect "on the go" VV set up. I ordered it from Health Cabin slow mail or cheapest way and received in almost 2wks later but I think thats pretty good considering..... Two thumbs up for the 1000mah