Ultrasonic transducers?

[Brian]

Anyone know of any good sources for waterproofed ultrasonic transducers (for
under $20)? Tried Google, without much success.
Brian

 

[Henry Kolesnik]

Fish and depth finder replacements?
Also ebay.

 

[Brian]

Fish and depth finder replacements?
Also ebay.

Sorry, I should've been a little more specific. I need it for proximity
checking, from 6 inches to about 20 feet. It won't be in water, but it will
be exposed to it. It's frequency needs to be about 40 Khz. I may need a lot
of them in the future.
Brian