... of ~30', andso setting-up goes quicker.The bubble is viewedpositively via a pentaprismand is monitored downthe eyepiece. ... freefootscrews is such thatthe bubble can be centredin a very short time.Independent oftemperatureUnlike the tubular level ofa traditional instrument, ... line of sight automaticallyEasy to level upThe advantage of thisinstrument is that, as soonas the bubble is centred,the line ...