Backup Battery: 3.7V, GSM: 850/900/1800/1900MHz, APP: TuyaSmart, Operation Temperature: 0~55℃, Wi-Fi: IEEE802.11b/g/n, Consumption: <55mA@normal, 500mAh Rechargeable Lithium Battery, APP Downloading: , Radio Frequency: 433Mhz, 1000mA, Power Supply: Mi cro USB 110/220VAC to 5V. Just check coupons out (with price alert and history). 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 Europe 
. I can’t tell you if this price is good – not enough records in my database, so I won’t judge.
Link: Banggood product page
1. ($44.99): BG28178d
2. ($50.04): Cuponation9
3. ($50.59): BG8ReviTrage
4. ($51.69): BG00c906
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BgcLuBofErtA10, BGAFF10OFF, BGCuponation10, BG62e7b5, BG46507f, 00c906, ADMITAD2212, 2022ACTIESNL, Terence, Tabby20, 2203ActiesNL, BG1efeb0, MVC8SPRING, BG79dd11, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, hoNEYbGdeAlS, BGJUNEGSG9, COUPONSDE1wk, BGcoupon8off, BGGutscheine, BG8OFFCOUPON, TTBLACK5, BG589b2e
(there’s a little possibility that old coupon will work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – GUUDGO Tuya APP Smart WiFi GSM Home Security ($-3)
Price history and price alert
Price history is not available for this item (not enough database records)! The lowest price was $40.99 though.
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)).