When connecting batteries in parallel, you add the capacity of the batteries together, but the voltage remains the same.
For example, if you connect two 11.1v 2200 mah 30C (66 amp) Lipo batteries together with this harness, you end up with an 11.1v 4400 mah 30C (132 amp) battery.
This is a great way to make use of your smaller Lipos in large models, saving the cost of purchasing large capacity Lipos that can only be used in large models.
The wire on this 'Y' Harness is 14 gauge with silicon covering for very good flexibility. It has one female T-Plug and two male T-Plugs. The length is 3 inches.