This belt is from a small wedding videographer's stock.  The batteries have been cycled and seem to be working fine, although no claims to amount of life or number of remaining charges should be inferred. 

 New Belts are selling for $389!  Get this one for less than 1/3 the price.

This is from the NRG Brochure:

This 4.9 lb. wonder is our most popular power product and is relied on daily by thousands of videographers the world over. From the serious "prosumer" to the full-time working professional, the Power-Pro+ is the basis of a sophisticated and affordable power system that can be expanded as a user's needs demand. The Power-Pro+ belt is a unique combination of power and comfort. 

It features:

• interchangeable high-capacity, memory-free, quick-charge-capable sintered Ni-Cad power packs
• Power chassis with dual inputs
• Battery pack change without shutdown
• Dual power outputs for powering two devices simultaneously
• 5-stage multi-color "Fuel Gauge" indicator
• Auto-reset overload protection for connected equipment.