What thermometer do you use?

I have a quick bbt therm. (Around 9 seconds)

It gets the job done. I can always clearly see my ov day. However, it is not super accurate. My chart isn’t always consistent.

But I am lucky & have such a big dip on ov day & a fast rise the next day. So it works for now.

Have looked for a new one on amazon. The reviews for every one are horrible! They break quickly, they’re not accurate...

I looked at iProven, mabis, easy@home.

Not gonna spend more than $15ish.

Recommendations??

TIA!