According to the specs which says the massager will operate up to 140 minutes on full charge i.e. up to 7 (seven) of 20 mins sessions. Since purchased, the best I could get on full charge were less than 3 (three) full 20 mins sessions then it just stops. Other than that it is a light weight, good design and nice looking massager. I'll probably buy again just to compare the battery performance, if the price is decent enough.