Here's what Nexi say about the Volume pedal:
The tone wizards at NEXI are committed to providing a unique vintage tone without compromise. The Volume VOL-01-UD pedal is the foot controlled pedal you need to have maximum control of your volume. The VOL-01-UD allows you to free up your hands and focus on playing notes rather than play with knobs. The pedal offers smooth volume control perfect for those times you need to swell a harmonic.
All NEXI pedals are True Bypass, are hybrid designed, and all are tailor-made to plug ‘n play so that you are the master of your volume from the get-go. This means the VOL-01-UD can be used standalone with a 9V battery, external power supply, or simply click it in NEXI’s revolutionary - The Solution - pedal board.
The creators at NEXI are all guitarists, with most having been on multiple tours and have even been awarded the Red Dot and iF Design Awards for their excellent product design. No one understands your needs better. The electronic board, together with the aluminium body is designed to be completely splash-proof; so beer spills will not prevent your awesome volume swells.