Working humidity: 0-95%RH, Working temperature: -10℃-+50℃, Model: WXCJKG11LM, Dimension: 86*86*15mm, Input voltage: 3V, Wireless standard: IEEE 802.15.4, WXCJKG12LM, Battery: CR2032(included), WXCJKG13LM, Sensitivity: -100dBm.
Basically copy coupon, view price history or create e-mail price alert. 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 China.
Link: Banggood product page
1. ($15.29): bGhOnEy10
2. ($15.29): BGSS10%SW
3. ($15.29): BgcLuBofErtA10
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): bgaqraled, BGCITYADS2019, AFfbG10, BGVDay10%off, BGLIGHT2020, BGAQA15, BGdragonBoat, bgshOOp10, BGLIGHT0920, BgoFErTaSchInA10, BGELIG0920
(these coupons are old, so probably won’t work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – Aqara OPPLE WXCJKG13LM Smart Switch Six Button ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for Aqara OPPLE WXCJKG11LM Smart Switch Double Button? There we go. The lowest price was: $10.99.
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)).