Fitness expert Harley Pasternak and actress Jordana Brewster lead a work out, on behalf of Fitbit, in front of the New York Stock Exchange, Thursday, June 18, 2015. Fitbit flexed some muscle Thursday and its shares rocketed 50 percent higher in the first day of trading for the fitness tracking gear maker. (AP Photo/Richard Drew)

Fitbit hit with a lawsuit

Several customers claim the Fitbit heart-rate monitor does not and can not accurately measure heart-rates as advertised.