Size 11.5*10*6cm/ 4.5*3.9*2.4inch(Approx.), Output Voltage 0~220V (Adjustable), Input Voltage AC 220V, Material Metal shell, Adjustable Voltage Range 0~220V, Weight Approx.500g, Max. Current 18A, Product name AC 220V 4000W Variable Voltage Regulator, Rated Current 9A, Max Power 4000W.
Go down and check coupons out. Remember to check price history if it is available. Do you want to know what the best price is?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
1. ($32.56): BG589b2e
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG6d2f05, hoNEYbGdeAlS, Cuponation9, BG8ReviTrage, BGcoupon8off, TTBLACK5
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for AC 220V 4000W Variable Voltage Regulator. The lowest price was: $18.99.
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)).