Working temperature 0℃~55℃, Protection level IP67, Product size 50x17mm, Product net weight 23g, Executive standard Q/QLMLO15, Wireless connection Bluetooth version 5.0, Battery type CR2032, Product model SJWS01LM, CMIIT ID 2020DP5425.
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. 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): BGXIAOMI664, BGYJ001, BG13767, BGXIAOMSA, BgcLuBofErtA10, BGXMCN51, 13f142, BGBTJU23, BGBTJU15, BGBTJUE6, BGMA030805, BGMA2902, BG10OFFAFF, BGAP2703, BGwhielabel, BGPL111, BGJUY281, BG10OFFAFF1, BGSE0101, BGOCXP136, BANGGOODSD, BGD11044, BGNOXP243, Terence, 2203ActiesNL, BG1efeb0, MVC8SPRING, BGJUNEGSG9
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi SJWS01LM Flood Water Immersing Sensor. The lowest price was: $12.55.
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)).