Great concept; COMPLETE waste of money.  The tubing that attaches to the glasses stays put OK, but immediately pulls off the cord making the whole thing useless.  Tried securing the tubing they use to the cord with heat shrink, but the tubing is slicker than snail-snot so nothing sticks -- which is really the issue in the first place, the tube doesn't stick to the cord.  Threw the thing in the trash after only having it for an hour.