EMD colorpHast™ pH Strips?

Hello has anyone ever use these before?. How accurate are they an also how long do you dip them into your wort for an at what temperature?.

I never had any luck with them. Could never see a color change.

I use them to see the ph level. But they dont give correct reading. I think. I dip them for 5 secs and compare on the bottle the color. Tells you ph level from 5 to 7. If correct

I’m not sure if they are the same brand but the strips I use seem to work but it is tough to tell what color it matches on the bottle they come in. If it looks close to 5 I go with it.

I think those colorphast strips are available in any drug store.