$39.89 – Monitor current: 0~6.5A, Monitor current resolution: 0.00001W, Monitor voltage resolution: 0.00001V, , Monitor current resolution: 0.00001A, Material: ABS, Monitor voltage: 4~24V, Monitor current accuracy: ±（0.5%+2）, Monitor voltage accuracy: ±（0.2%+2）, Monitor current accuracy: ±（0.5%+2）, Monitor power: 0~156W.
When I was updating this page, then coupon price was $39.89 for FNB48 USB Tester Voltmeter Ammeter with Bluetooth (in Banggood). Get coupons, create price alert or check price history out! What is best price?
Latest coupon and price update (UTC):
Banggood ($39.89)
Banggood warehouse is located in China. The question is – is it a good price? This price is higher than average price ($35.59) for this item. Only one coupon available!
Link: Banggood product page
Price without coupon: $41.99
1. ($39.89): BGMAI666
put item in your cart and apply coupon code there 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): BG8OFFCOUPON, BGGines, BGM1TOOLS88, BG20236Tool, BGTOOS729, BG8FORMULAMX
(these codes were not working in latest coupon update, but you can check them out anyway)
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.
Price history and price alert
Here is price history (for all/most countries) for FNB48 USB Tester Voltmeter Ammeter with Bluetooth. The lowest price was: $33.99.
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)).