Hey everyone... was wondering if you have a pulse oximeter for at home?

I found this one on Amazon, and the reviews look good. Wondering if anyone has brand they like/dislike or any experience purchasing one- what to look for etc?

ok- I am not allowed to post links yet, lol... if you go on amazon look for "Finger Pulse Oximeter SM-110 with Carry Case and Neck/Wrist Cord" Prime has offered for less than $40 (usually $199)

Googling also turned up one that will connect to an iphone iSpO2 and has an ap that will record history etc. Anyone tried it?

Thanks in advance