Best BBT thermometer?!

Kayla • Mommy to 4 year old Kimber Elaine and 2 year old Kylie Jean. 3 early miscarriages in the past 5 months and newly pregnant again. Praying for a sticky baby ❤️

I’ve tried a few different kinds but would love to know y’alls opinion on the most accurate? My chart just seems all over the place!