Hardened Power Systems BatPac MK4

Innovative & simple, the BatPac is a problem solver. The Velcro straps wrap securely around a common RBC4 SLA battery (not included), providing quick, reliable DC connections for power and charging.

http://www.portableuniversalpower.com/batpac-rbc2/

Perfect for Go-Bags, field day, and daily use.
Incredibly handy in the shack, vehicle, or on the go.
Never worry about shorting battery contacts again.
Flip the volt meter switch and confirm you have power.