This portable spot welder machine is a game-changer for DIY enthusiasts and professionals alike. With its compact design and built-in power supply, you can now easily weld- sheets. DIY spot welding, which combines the built-in power supply and the welding pen into one, without the need for an external welding pen to easily weld-, make your spot welding project easier and . The integrated soldering pen uses gold-plated terminals, with good conductivity and low contact resistance. Miniature USB charging interface is adopted for easy charging. Fine workmanship and good-performance.Easy to use&Long service life. Operation method: 1. Shot the key to turn in the machine,long the key for 3 seconds to turn the machine; 2. After startup,the module is in automatic welding mode,welding once in 2 seconds; 3. After starting, you can change the output power of the spot welding machine by pressing the key,and the blue light indicates the gear; 4. that the battery welding in free of rust,clean and smooth; 5. that the sheet is clean and smooth; 6. Welding head detection contact metal,can be output once,after lifting can be welded next time; 7. Set up the spot welding machine,appropriate pressure to make the welding needle and , and battery contact is good,no hanging on bad contact,can be welded.Different thickness,using different gear,not the greater the power effect is batter,you can try which gear is more suitable. Model:-401 Charging:Micro-USB 5V Battery:18650/21700 Lithium-Battery Note:Do not for touch-any metal parts of the fuselage-with a welding pen. Colour:Black Material:aluminum alloy Size:about 249.7x57.83x24.45mm/9.84x2.27x0.96in Package Contents: 1 * Spot Welder Machine Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.