I feel it should be clearly stated somewhere that it has a max speed durability. In my tests recording voice mail messages, I will say that the voice is clear but somewhat tinny, distant with a bit of a compressed digital sound to it. After trying many other shoe cleaners OMG is simply the best! It can also work in corded mode which helps when the battery is dead and you can stay connected. Stay far far away! Since I bought this product it immediately became a shame for me. Bought this for my husband and son to use this summer. Great addition to my home gym The ONLY down side to this is that my arms rub on the upper sleeve area rubber. Dear Alpine Swiss store.