For sale is a really cool late 60s-70s Schaller F121 'Fusschweller' volume pedal, made in West Germany.
 
Does what it says on the tin - these were simple volume swell pedals that allow the player to increase/decrease the output of their instrument, allowing for effective control of volume.
 
Solid and well built, this one is in excellent condition given its age and even comes with its original box (often discarded).
 
Not a holy grail pedal by any means, but a great vintage and fully functional unit with some good utility for live playing.