With two vials, for both vertical and horizontal measurements Laser level lineSpecifications:With two vials, for both vertical and horizontal measurements2 lines with 90 degree angle Laser sources: two 635nm laser diodeLaser safety class: class II, less than 1mWOperated by DC 3V (2*LR03 AAA batteries, not included) Laser level line,With two vials, for both vertical and horizontal measurements