The Volcano hotend lowers the nozzle closer to the print bed. This BLTouch mount moves the BLTouch 7.5mm closer to the print bed to account for the longer Volcano hotend.

You're probably fine printing in PLA, but I'd still print in PETG/ASA since it's close to the hotend.

This mount is designed to fit Ender3 printers and a BLTouch probe and uses the existing M3 hardware included for the BLTouch