Resolution: Blood Oxygen Saturation ± 1%, Display HD Two Color OLED Screen, Weight 54g, 70% To 79% Within The Range Of ± 3%, Ambient Humidity: 15% To 80% When Working 10% To 80% Storage, Atmospheric Pressure: 86kpa ~ 106kpa, Size 62x 32x 33 mm, Operating Temperature: 5 ° C ~ 40 ° C, Color Blue / Yellow / Green / Pink, Storage Temperature: -10 ° C ~ 40 ° C, 70% Or Less Is Not Required, Material ABS, Measurement Accuracy: ±2% Within The Range Of 80% To 99%, Measurement Range: 70% To 99%, Power Supply 2x 1.5V AAA Battery (Not Included).
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:
Banggood
Banggood warehouse is located in China.
Link: BOXYM YK-80X Oximeter
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Additional Banggood coupons:
1. First page
2. Second page
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – BOXYM YK-80X Oximeter [EU] ($-3)
Price history and price alert
Check out price history chart (for all/most countries) for BOXYM YK-80X Oximeter. The lowest price was: $12.99.
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)).