I noticed these in our local branch the other day. No idea of the quality or durability but it may be useful for some. Here's the info.
A search for "ultrasonic cleaner" on FPN gave 118 results. Have a read of some of these posts for some background information on the usefulness of such a device.
PS: in the interests of balance, I also shop at Waitrose.
Edited by twdpens, 29 January 2014 - 10:20.