This is a a two channel micro mini handset operating on 40.685MHz.
Easy to identify against other handsets in the range by the colour of the buttons which are light grey.
Used on older Hormann garage door openers operating on the 40.685mhz radio frequency.
Please note this is not compatible with the newer version of this handset which has the light blue buttons.
Hormann stock reference 0437112.
Video shown is from the HormannDoors youtube Channel