This is the Traxxas 3S, 11.1V, 5000mAh, 25C Power Cell Li-Poly Battery Pack with iD Traxxas Connector. This battery requires a Traxxas iD equipped LiPo charger to balance-charge!

All Traxxas iD Power Cell Battery Packs are optimized for free-flowing power and maximum punch with premium quality, low-resistance cells; flexible, silicone-jacketed 12-gauge wire; heavy-duty welded tabs; and patented Traxxas high-output, gold plated, High-Current Connectors.

High-Current Connector
Revolutionary concepts come in all shapes and sizes, and the patented Traxxas High-Current Connector defines the new standard for efficiency, ease of use, and high-current handling. On iD-equipped Traxxas LiPo batteries, the balance connectors are integrated into the Traxxas High-Current Connector eliminating fragile balance wires and connectors, along with the need for external balance boards.

Charging with a Traxxas iD Charger
The Traxxas iD battery system is the easiest and safest way to charge your Traxxas batteries. The EZ-Peak Plus (TRA2970) recognizes Traxxas iD batteries and in an instant automatically configures and optimizes the charger settings. Theres no need to be a battery expert or learn how to navigate complex menus. Just plug in a Traxxas iD battery and EZ-Peak Plus does all the work for you.

Features:

• Semi-Rigid Construction: Traxxas Power Cell LiPO packs use a unique construction method that results in a firm, rugged, and compact pack that does not require a hard case. This allows Power Cell LiPos to offer greater capacity in a given size, and also allows the user to easily monitor the condition of their battery. Unlike a hard-cased pack, if a Power Cell LiPo puffs or softens due to damage or abuse, the user can easily see and feel the change in the pack. Plus, there are no wire harness connectors that can loosen and fail over time.
• Oversized Discharge Tabs: Power Cell LiPos are constructed of premium cells with extra-wide discharge tabs. The discharge tabs are the actual contact points between the cells, so maximizing their surface area is critical to maximize pack performance. Power Cell LiPOs extra-wide tabs ensure minimum resistance so more power and capacity is delivered on every run.
• Hard-Wired for Maximum Durability and Performance: Power Cell LiPo packs feature High Current Connectors with 12-gauge Maxx Cable wire, soldered directly to the LiPo cells. Bullet connectors found on other packs introduce additional connections, increase resistance, and allow accidental reversed-polarity connections. Power Cell LiPos rugged, hard-wired connection minimizes resistance to make sure all the power from your battery is used for greater speed and longer run times.
• Maxx Cable: Every component of a battery pack contributes to its performance—and that includes the wires. Traxxas Maxx® Cables 12AWG multi-strand wire offers extremely low resistance so power is not wasted as heat, and the fine strands allow excellent flexibility for easy installation and reduced stress on the packs solder joints. Soft, silicone insulation protects against shorting without compromising flexibility. Maxx Cable is simply the finest and most efficient wire available, and the only wire good enough for Traxxas Power Cell battery packs.
• Center Wire Exit: Traxxas LiPo packs have a center wire exit to properly fit Traxxas models with wire reliefs in the chassis. You get perfect battery fit without crushed wires or cut insulation—that means longer life for your LiPo battery.
• Factory Fit: Traxxas Power Cell LiPos are designed to fit Traxxas models so you get the most capacity possible. Forget the foam blocks! Special 7-Cell sized pack configurations maximize the capacity in your Slash, Slash 4×4 and other Traxxas models. The wires exit from the center of the pack to line up with the relief channels in Traxxas chassis for a pinch-free fit. There are packs for every Traxxas vehicle, each guaranteed to fit properly and deliver the performance built into our models.

Specifications: 

• Type: LiPo 
• Total Capacity: 5000 
• Voltage: 11.1 
• Continuous Discharge: 25C (125A) 
• Max Burst Rate: 50C (250A) 
• Watt Hours: 55.5 
• Charge Rate: 1C (5A) 
• Max Charge Rate: 2C (10A) 
• Dimensions: 155x26x44mm 
• Weight: 13.3oz (376g)

NOTE: This battery requires a Traxxas iD equipped LiPo charger to balance-charge! 

Spec

• Brand: Traxxas
• Part No: TRX2872X
• Barcode: 020334287298
• Voltage: 3S – 11.1v
• Fitment: Option Part
• Case Type: Soft Case
• Connector: Traxxas