In the words of JAM Pedals:

Comprised of 4 photocells, a bulb, original NOS 2SC828 transistors
and carbon comp resistors, the RetroVibe mk.2 delivers the majestic
sounds of the best Uni-Vibe pedals from back in the day, but housed in a
modern pedalboard-friendly enclosure and featuring standard 9V DC
operation, internally lifted to 15V DC.