Press Pause On Sperm

The future of male contraception? Doesn't look too easy to me:

A surgeon inserts a silicon chip into the vas deferens. A key fob sends out RF waves, just like the key to your car. The silicon chip converts the RF into acoustic waves, which in turn induce movement in the material, allowing it to expand and seal the tube. Sending another pulse from the key fob lets the material contract allowing sperm to pass.