Fossil Flight - CH2824 Watches : One Size "au4005" Questions

I have a abacus au-4005, how does it work.how do i test the batteries ? au4005 not change no power,phone #313-729-7370 name delton

My Abacus Fossil AU4005 110504 wont charge any more,wen i put it on the charger nothing happen,it does not light up any more,do i need a new battery and where do i get it? MY WRIST NET ABACUS AU 4005 ...