Pettersson Elektronik AB (Sweden)
- Bat detectors
- http://www.batsound.com/

Belfry Bat Detector
- Hand built to order, an assembled unit that is portable, small, lightweight and is powered by a 9 volt battery.
- http://www.econvergence.net/batdet.htm

Bertrik's bat detector page
- Information on building your own bat detector
- http://www.home.zonnet.nl/bertrik/bat/bat_indx.htm

Ultra Sound Advice (UK)
- Various ultrasound devices (air ultrasound, bat detectors, and data logger).
- http://www.ultrasoundadvice.co.uk/

Stag Electronics
- Bat detectors, books and CDs of bat echolocation, downloads of bat sounds and bat music.
- http://www.batbox.com/

Convergence Technologies, Inc. (USA)
- Bat detectors
- http://home.earthlink.net/~infocentr/faq.htm