pedometer issues and need a recco :)

Hi everyone, I am new here. I have two pedometers (coolfire 3d pedometer) and a 3dtrisport. Both are good; but the Coolfire always shows a good deal more steps and the trisport always underestimates the distance! I have calibrated the trisport, but not sure how to calibrate the coolfire. Anyway, couple questions:

1. is there a way to calibrate the trisport so it better reflects mileage? Or to calibrate the Coolfire at all? More important....

2. Is there a pedometer that is generally considered the most accurate, and that people here strongly recommend? Not really looking for one that uses an app, though not ruling it out. I don't always have my phone with me though and I like the simplicity factor.

Thanks in advance, fellow walkers! Appreciated in advance!