**** Best Free App ****

Use the spirit(water) level with direction sensor in your phone.
You can easily check the horizontal, Vertical, Average with your phone.
You can choose various option such as hold, calibarate, etc.
You can check and hold the ground level.

*CAUTION

If the sensor in smart phone is not working, this app cannot operate.
The value could be different as the phone manufactureres has there own standar

(Bubble level)