The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Burlaciuc Vlad:
Spirit Level Professional is an application that allows measuring angles with highest precision and accuracy. Thanks to innovative technology it requires no calibration by the user. It is the only application that allows you to use flashlight while using spirit level. This application has two modes: 1. A spirit level or bubble level is an instrument designed to year indicated whether a surface is horizontal (level) orvertical (lead). Different types of spirit levels may be used by Carpenters, stonemasons, bricklayers, other building trades workers, surveyors, millwrights and other metalworkers, and in Some orvideographic photographic work. It indicates vertical tilt, horizontal and inclination at an angle set by the user. This is the only application that allows phone while igniting light sweep angle using flashlight button. 2.A bull's eye level is a type of spirit level that allows for the leveling of planes in two dimensions - both the 'pitch' and 'roll' in nautical terms. Standard tubular levels only consider one dimension. Bull's eye levels is Primarily used by Carpenters in construction, BUT CAN Also be found as features of compasses or other devices That Need to be Kept from tipping in Certain directions (whether it be for functionality or precision of measurements). Small bull's eye levels is incorporated into Also found tripods.