Operating frequency 433.92Mhz ± 50KHz, Power supply Solar power charging, Working temperature -20 °C -75 °C, display way LCD display, Operating voltage 3.7-5 V.
You can create price alert here, copy coupons and view price history. 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 code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($28.15): BGSCM75
2. ($29.11): Cuponation9
3. ($29.43): BG8ReviTrage
this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): 8BGwbg2204, tRaDetRaCKeR, BGAUTO22, BGdcbfa8, 9OFFSUMMER
(probably won’t work, but you can try them out)
Price history and price alert
Do you need price history chart (for all/most countries) for Solar Power TPMS with 4 External Sensors? There we go. The lowest price was: $19.99.
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)).