Put it in if you like but it is for longer zeros as Andy said, where an atmospheric change could put your zero a couple inches high or low so the app can account for that.
I just put in a...
Type: Posts; User: veitnamcam
Put it in if you like but it is for longer zeros as Andy said, where an atmospheric change could put your zero a couple inches high or low so the app can account for that.
I just put in a...