The Fishman Rare Earth Pro-Rep-102 Humbucking Soundhole Pickup is for musicians who want the warm, full humbucker acoustic tones. A volume wheel is conveniently located onboard. Battery life rated at 300 hours. Powerful neodymium (a rare earth element, hence the name) magnets are responsible for the excellent sound quality and string to string balance of this active, double coil magnetic soundhole pickup.Re-voiced and fine-tuned for smoother treble response Cutting edge neodymium magnets produce a warmer, more naturally acoustic tone Active electronics for a pure, clean sound Newly designed mounting system and ergonomic body shape Excellent string-to-string balance Miniature batteries (included) mount conveniently on the underside of the pickup Fits in soundholes as small as 3-5/8" (92mm) diameter Pre-wired output jack can also be endpin mounted Easy installation with no alterationplug and play right out of the box Convenient, accessible onboard volume control Battery life rated at 300 hours