ZigBee Wireless Connection / APP Control / Multi-purpose Smart Home Security Equipment.
Basically copy coupon, view price history or create e-mail price alert. What is 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 price update (UTC time):
Banggood
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): 10XMA, 20XMAQ, d173d2, 256310, DAQIR, 360878, BGMAQDS, affiliate6, aff7off, BG7AQDWS, bgssaff9, BGaDmITAd, BGAQDSS9, 13f142, BGhumankit, BGBFAFF2019, BGAQDSS1, BGCITYADS2019, BGZIGBEEPL, BGAQDS, BGAQ20, BGHOMEAPP, BGAQA15, BGAQDS04, bGhOnEy10, BGSM15, BGSMOFF, BGAQWDS7, BGAQADOORS, bgshOOp10, BGAQDSUK, BGSAMRTH, BGN7CND, BgcLuBofErtA10, BGAQDSH, BGAQDSB, BGAQDSU, BG15SH12, BGAFF10OFF, BGSTHO15, BGAQZUK, BGAARDS1, BGCuponation10, BGAARDS2, BGAQDSSS, BG3d0660, BGd2c614, BGHONEY2110, BGSHOM15, BG571878, BG133c4e, BG40bece, BG200eff, BG78a9e0, BG87e1d2, BG46ecc4, BG0086c3, BGZJ323, BGGROC323, BGcou323, BGSLO323, BG115048, BG35eaee, BG015156, BGCL1323, BGCL323, BGHO323, BGcou925, BGNDH59, BG2f4c49, 6GSGIT, BGf3a810, BGD11047, BG15d2dc, BGB5059, ADMITAD2212, BGSmart6, BGHU1863, BGPLWIOSNA62, MVC8SPRING, 8BGwbg2204, pROMo8cuPoN, BGJUNEGSG9, Cuponation9, 9OFFSUMMER, BG8ReviTrage
(probably won’t work, but you can try them out)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Xiaomi Aqara Window Door Sensor [EU] ($-3)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Aqara Window Door Sensor. The lowest price was: $4.99.
Price records source(s): Gearbest, 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)).