Search very small ultrasound emitter\receiver

I am looking for a very small emitter/receiver ultrasound. Not to be confused with the distance meter. The device must be 2 in 1. Switch mode. Or should register a signal if it does not send. Only analogue. Very low power, up to 20 cm. No longer required. Without resonator. Looking for all day I can not find:(.

Ultrasound transducers for air are typically resonant to get any kind of efficiency at all.

This sort of thing is what I've seen:https://uk.farnell.com/multicomp/mcusd16a40s12ro/transceiver-40khz-16mm-metal/dp/2362677

Hi,
Welcome to the forum.

What is the application?
What do you want the "ultrasound" to do?

Thanks... Tom.. :slight_smile:

Have you thought of a small bat?

MarkT thanks you gave the best I've seen ))