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Welding thickness of fixed welding head: 0.15-0.35mm, Welding thickness of welding pen: 0.05-0.2mm, 50Hz, 2 Pulses time: 1-10ms, 4 Pulses time: 2-20ms, 60Hz / AC 220V±20V, Power: 4.3KW(Instantaneous), Welding current: 120A-1200A(Push up welding mode), Net weight: 7kg, Input voltage: AC 110V±20V, Size: 140x245x200mm, 8 Pulses time: 8-80ms
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($332.80): BGherra
2. ($332.80): BGWELDTOOL
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGPToo15
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Do you need price history chart (for all/most countries) for SUNKKO 737G+ Battery Spot Welding Machine? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).