Another user found this:
It looks like a good option, assuming the vswr chart is accurate.
Please note, this has 3ft of low loss cable. Similar antennas have have 9+ feet of cable that is -.3db per foot at 900Mhz! Way too much loss for these low power devices.
I’d order one and test it but I’ve spent my project budget for the month. Maybe later.
There is a discussion about this here: Car roof magnetic antennas - Meshtastic