Battery Capacity: 2000mAh Lithium Battery, Color Rendering Index: Ra90, 4 Lighting Modes: 5000K 100% Brightness / 4000K 100% Brightness / 3200K 60% Brightness / 2700K 10% Brightness, Light Head: Magnetic Mounting / Adjustable Angle, Duration Time: 100% Brightness ≥4 Hours / 60% Brightness ≥7 Hours / 10% Brightness ≥40 Hours, Anti-Blue Light Hazard Rating: RG0, Charging Port: Type-C.
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Aliexpress
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Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There are no active coupons for this product, but the price is pretty low isn’t it?
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG589b2e, BG8FORMULAMX, BG064a6b, BGef8193
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Mijia 2000mAh Rechargeable Desk Lamp. The lowest price was: $19.99.
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)).