BaroTool

Want to know at what level a hill is or a tower?
Check this very accurate altimeter from a reference level.
Capable to measure the difference even if you just raise the device from your waist to your eyes.
You may reset to zero level and start a new session.
Please note your device must have a barometer. Such as iPhone 6 and later, iPhone SE excluded.
Or latest models of iPad (mini 4 or Pro)