L.R. Baggs Element Active System Undersaddle Pickup with VTC Volume and Tone Control

Features:
One size fits most common string spacings and saddle widths
Even string-to-string balance
Includes easily-accessible yet unobtrusive soundhole-mounted volume and tone controls
Pre-contoured discrete class A endpin preamp
Comes with Battery Bag for secure and unobtrusive battery retention
Available in steel- and nylon-string versions

Specs:
Pickup active sensor length: 3.4"
Pickup thickness: .038"
Pickup width: .092"
Battery type: Single 9V
Battery life: 1000 hrs.