We believe that this new batch will have improved reliability based on our testing.

True Spec Extreme 7.4V-4000mAh-115 Amps/150C Shorty 5mm Inboard pack. ROAR Approved

The Extreme shorty has the lowest possible intenral resistance for a shorty size which means t has more voltage under load.  This pack is perfect for the stock classes or modified classes when maximum punch is required.   We offer a 5mm to 4mm adapter for those who still want to use 4mm male connectors.  Click here for the adapter.

5mm gold plated pure copper adjustable connectors

- Built with wide tab cells for lowest possible internal resistance.

- 5mm pure gold plated copper tubes opened on both sides of the case.  

True Spec Extreme Notice:

We have been getting several inquiries about the proper use of our True Spec Extreme packs. They are high end, all out packs that will give you the best possible performance. The “but” with this, is like all maximum performance products, they are not for everyday use. Have you seen a NASCAR motor going 100 000 miles? Or a sprinter running a marathon? Our True Spec Premium packs offer great on track results and are the go-to pack for regular users. Those that need the extra punch and lower resistance, such as stock racers or insane speed run racers, should use the True Spec Extreme packs, noting that like a F1 motor, their ultimate life is much shorter than an econobox 4 cylinder mass production engine. Since these packs are pushed to the limit to give maximum performance we will only warranty packs that have a cell go bad within the first 6 months of use.  This doesn’t cover packs that expand or swell.  The active nature of the materials used in these packs tends to create more natural expansion of the cells then regular packs.  Only use these packs if maximum performance is required at the expense of some cycle life and reliabiltiy.


Pack Specs
Milliamp Hour 4000mAh
Voltage 7.4V
C Rate 115 Amps / 150C
Configuration 2S2P Hard Case
Connector Type
Inboard 5mm Gold plated pure Copper 5mm tubes. 2mm balance tube.
Length 96mm / 3.78in
Width 47mm / 1.85in
Height 25mm / 0.98in
Weight 212gr / 7.47oz

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True Spec Extreme 7.4V 4000mAh 115 Amps/150C Shorty 5mm Inboard

  • Product Code: 40115-2S2P
  • Availability: In Stock
  • $44.95 $34.95