Altitude: <=2000m, Storage Temperature: -10 ~ 50°C, Humidity: <=75%, Item Weight: 229g / 8.1oz, Live Wire: 50mm, Temperature for guaranteed Precision: 18 ~ 28°C, Operating Temperature: 0 ~ 40°C, Package Weight: 345g / 12.2oz, Wood(with a minimum volume of 20x16x4cm): 20mm, Power Supply: 9V Battery(Not included), Item Size: 21.5x 8x 3.5cm / 8.5x 3.1x 1.4in, Package Size: 23.5x 9x 5.5cm / 9.3x 3.5x 2.2in. You can create price alert here, copy coupons and view price history. What is best price?
Aliexpress
I could not find it on Aliexpress. 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. We have found one coupon for this product!
Link: Banggood product page
1. ($69.69): BGherra
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): 502C6B, aff7off, TTxBG10, AFfbG10, BGVDay10%off, BG0224MD, BG387B
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for UNI-T UT387B Wall Metal Detector is here. The lowest price was: $42.99.
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)).