The Sounder S500 incorporates a high-power transmit amplifier, which can get hot in normal use. We highly recommend aluminum standoffs (or other thermally conductive material) for mounting, and if these can be connected to other metal components for additional heat dissipation, all the better.
Important: There is firmware protection so that the ping rate will be reduced if the temperature gets too high. So, adequate cooling will ensure maximum performance.
See more info on mounting options