Starttæki 12V/24V Startronic Supercap

Designed for 12 and 24 V vehicles, the STARTRONIC SUPERCAP 12/24 V is an intelligent autonomous starter with
no internal battery. It’s internal supercapacitors can be recharged using either the residual voltage of the vehicle
that needs to be jump-started, or more quickly using the battery in the recovery vehicle.

https://planet.gys.fr/pdf/datasheet/uk/082816.pdf