The people have spoken, and we listened.  Our storage PLUG accepts two CR123, AA, or AAA batteries.  It also has a slot for a single CR2032 battery, a pocket for a small Allen or Torx wrench, and a slot for a MultiTasker NANO Tool.
Got meaty hands?  We've got you covered.  In addition to the storage, the PLUG also extends the length of the grip .25" and squares off the back of the grip to fill your palm.
 
SPECS AND FEATURES
Made in USA
Compatibility: Kung Fu Grip
Height: 1.5"
Weight: .7 oz
Retention: Friction
Material: Durable Rubber
Water Drainage Holes on the Bottom
Skittles Compatible: YES