This EA Motorsports lipo is the recommended battery for your GZ1.  Even though they are rated as a 5100, they test out with the same capacity as the Reedy 5300 packs.

The 80C Team EAM Li-Po battery packs feature a completely new chemistry that offer the lowest resistance and highest voltage output available for greater performance in all classes while still maintaining one of the highest life cyles in the industry.  All packs are QC checked and tested to ensure it meets Team EAM standards for quality and reliability.

• Hard Case for cell protection.

• Higher voltage output for all racing applications.

• Lower internal resistance.

• Gold plated bullet connector.

• 5100 mah 80C rating.

* All packs are tested using an IR meter to test the true internal resistance of the pack to ensure quality and reliability before leaving the shop.

* Reusable storage box included with each pack.

* 2S Lipo pack

* ROAR Legal.

*these batteries drop ship from EA  motorsports.