Working voltage 3V, Green light Suitable for moisturizing, Red light Water shortage, Weight 30g, Working current 10uA, Size 131x 25.1x 10.9mm / 5.16x 0.99x 0.43inch, Rated power 0.03W, Battery 1x 3V CR2032 button battery (not included), Color White, Product name Flowers and plants detector, Blue light Too much water, Material Shell ABS plastic + detection sheet material-glass fiber epoxy copper clad board, 05, Measurement accuracy -0.
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.
Updated: 01-08-2025
Banggood
Warehouse in China.
Link: Smart Sensor Plant Flower Monitor
$9.99 with coupon: BGcaa3e6
$13.80 with coupon: BG1efeb0
$13.95 with coupon: Terence
$13.95 with coupon: 2203ActiesNL
$14.10 with coupon: BG00c906
Additional Banggood coupons:
1. First page
2. Second page
Price history and price alert
Check out price history chart (for all/most countries) for Smart Sensor Plant Flower Monitor. The lowest price was: $4.29.
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)).