The Molicel P42A 21700 battery is a top tier battery, beating even the current purple-wrapped king. It carries a typical 4100mah capacity and offers a continuous discharge rating of 30A (40A in cooler conditions, but stay safe out there). As you'd expect from a top level producer of quality like Moli, the P42A has a super low resistance, quick charging time and peak pulse discharging of up to 45A.
Basically, if you own a mech, you NEED to try these. After the excellent 20700 cells all around the world, the P42A is a best in show 21700. Check out Mooch's review here, of "one of the best batteries available".
Specs:
Rated Capacity: 4.0Ah (Minimum), 4.1Ah (Typical)
Rated Charge: Limiting 4.2A and constant 4.2V charge for 1.5 hours or 50mA at 23C.
Rated Discharge: constant 0.84A discharge until 2.5V at 23C
Nominal Voltage 3.6V 
Shipping Voltage: >3.45V (approximate state of charge on arrival <30%)
Internal Resistance: <15mΩ (measured by AC impedance at 1kHz)
End of Charge Voltage: 4.20±0.05V
End of Discharge Voltage: 2.5V
Charging Time: approximately 90 minutes
Maximum Charging Current: 8.4A 
Maximum Discharging Current: 45A (this is NOT continuous)
Operating Temperature:
Charging: -20~60C
Discharging: -40~60C
Storage Temperature: <35C, recommended <23C for long term storage
What's in the box:
1 x Molicel P42A 21700 Battery