Standby current ≤30uA, Working temperature -10 ℃ – + 55 ℃, Transmitting power ≤15dBm, Battery life More than 1 year (20 times / day), Communication distance 50 meters (open area), Humidity error 5%, Temperature error 0.5 degrees, Working voltage 3V, Size 61x23mm, Low voltage alarm value 2.5V ± 0.2V, Mainly depends on whether the network distance of the gateway is covered, Working current ≤30mA, Model BW-IS4, Wireless type ZigBee, Installation method Wall hanging.
Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
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. ($17.09): BgcLuBofErtA10
2. ($17.99): 13f142
just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): 2020CNY, BGBWS41, BGVDay10%off, BGSAMH, bGhOnEy10, BGBWIS4, BGSM15, BGBWUU1, BGSMOFF, BGBWIS4A, bgshOOp10, BGSAMRTH, BGBWIS4P, BGBWIS4C, Cuponation9
(I don’t think these’re gonna work, but you can try ’em out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – BlitzWolf BW-IS4 ZigBee Smart Temperature Humidity Sensor [EU] ($-3)
Price history and price alert
Price history (for all/most countries) for BlitzWolf BW-IS4 ZigBee Smart Temperature Humidity Sensor is here. The lowest price was: $13.99.
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)).