Characteristic: 1. There is a window on the back of the drive part, you can add copper or tin yourself. 2. Added external pads for the LED diode and buttons on the board to facilitate the connection of the LED\u0026 buttons on the board with other places. 3. The upper and lower MOS design is bold and tinned to reduce internal resistance and increase current. Technical data: Material: PCB Color: Black System Voltage: 12V14,6V Operating Current: 90A150A Suggested battery (NOT included): 2045ah lead-acid battery with good performance and low internal resistance do Aerodynamic Modeling 3,55,5 Ah 45C 3S 3035ah Lithium Battery Pack Suitable do lithium battery/26650/32650 lithium battery 190*110*30mm / 7.48*4.33*1.18in Package weight: approx. 200 g / 7,05 oz Note: Spot welding involves local rapid heating and high current cooling, which requires sufficient power supply. In general, the welding current of nickel-plated sheet metal with a thickness of 0,1mm0,15mm is about 90A150A, so the working power supply of the circuit board must be greater than or equal to 150A. Packing list: 1 * main circuit board 2 * input cable 2 * Welding Pen Output Wire 1 * Welding Element Set (Tin Strips Nickel Sheet Ears with Copper Insert Screws Shrink Tubing)