The Magenta Bat4 Bat Detector is a completely new detector developed from our experience with previous designs.
All the good features of the original are there, including high level audio output, and built-in front-facing weatherproof loudspeaker.

Advanced low noise IC preamplifier stage
High stability ‘easy tuning’ linear heterodyne oscillator
New audio circuits
Increased gain and sensitivity
Convenient bottom mounted headphone socket (mutes Loudspeaker)
Line level tape recorder socket – constant level regardless of volume control
Low noise Analogue MEMS microphone with extended high frequency response
Top lit calibrated frequency dial

instructions can be found at:
https://magenta2000.co.uk/wp-content/uploads/2022/12/Bat4ProductSheet.pdf