My on-Rezendentin "Karo" is absolutely right: Russian Roulette. My delivery of 4 units was only 1 working, from the other 3 I built a second together that works halfway (because of the ridiculous switch times yes and sometimes no). Above all, I realized with shock and anger that it is already used devices whose battery contacts rusted and small tapping screws that hold the casing Been overexcited, so no more careful were tightened (with watch tools). So, folks, steer clear of this product !! As also benefit the loving packing of the goods by the staff and the addition of gummy-Drops nothing. jsmith