24V Booster Pack for Active Guitar Pickups. Includes Batteries. 9 Volt Battery Not Included But Shown in Pics For Size Comparison. This Pack is Slightly Bigger in Size Then The Older Pack, Still Roughly Same Size As a Single 9 Volt Battery. Slightly Wider..  Regular 9 Volt Size is 47.5 mm x 25.5 mm x 17 mm.. This Battery Pack Measures 45mm x 27mm x 17 mm.  Any Questions Please Ask.