Femometer....

Hello , i have been using opks now since for years and I do know how they work , anyway , due to me running out last min i’ve had to buy some different brands , so i ordered the femometer but untul the arrived i had to go and buy cheap ones from the store where I live ... anyway tonight i took them both to see what both of their results came back as and as you can see the shop brought one ( blue is nearly positive ) but the femometer is completely negative i do understand that my shop brought ones isn’t a positive yet but it’s nearly there right .... not sure what to think , it’s my first month back at ttc after loosing a baby , there for not sure when i’m going to ovulate or when my next af will be so i’m counting on these opk’s really but now i’m just confused ....

What’s your opinion on these ?

Should i trust femometer or the shop brand ?

What’s your experience with femometer?