I am putting a star because the bubble level on top is not straight. It's easy enough to install, but I buy a level and expect it to level. Other than that, it's an inexpensive transition/level that offers the features I need at a reasonable price. Note: the manual says to check the level, use a high precision level to set the breakpoints. If I already had a high level of precision, why would I buy it? It looks like the factory that built them had the tools to set these levels before they shipped them.