Standby Time: About 40 days, Resolution: 240*240pixels, APP Name DaFit, Charging Time: About 2.5 hours, Type: TFT, Battery Capacity: 280mAh, Charging Type: Magnetic Charging, Size: 1.3inch, Bluetooth Version BT 5.0, Personalized Watch Face Support, Blood Oxygen Monitor Support, Waterproof 5ATM Waterproof, Using time: About 15 days.
Just check coupons out (with price alert and history). You probably want to know what is the best price?
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 coupon and price update (UTC):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
1. ($17.99): BG8a509b
2. ($40.24): BGc70579
this code has to be applied 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): band10, BGWRIBAND10, BGb58412, BG51f436
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for UMIDIGI Uwatch 3S Fitness Tracker is here. The lowest price was: $17.99.
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)).