A line laser level gives the user accurately horizontal or vertical illuminated lines. These lines are projected on a surface the laser line level is laid against. Usually line laser levels are used in the construction and cabinetry industries and some models are inexpensive enough for do-it-yourself applications. In construction industry, a line level is good for finding out how level the wall you are building is and how it corresponds to the wall you need to build on the other side. Some models of the line laser levels project a cross on to the wall. This feature is very useful if you need to have a horizontal line as well as a vertical level line. The cross feature, is ideal for putting up pictures and shelves or anything that you need to attach to the wall and that must be level.