Rotary Laser Levels produce a level laser line around a work space in 360 degrees. Some models are for indoor use only, and some models will handle indoor and outdoor use. Rotary Lasers are manual-leveling or automatic-leveling types (automatic-leveling are also sometimes called "self-leveling"). If you plan to use a laser that is made for outdoor exterior work, you will need a laser detector (detectors are also known as receivers or sensors), since the laser beams cannot usually be seen by the human eye in bright conditions. Plus, detectors generally increase the distance that a beam can used.
Also understand that some Rotary Lasers will handle "Grade" which means their beam will tilt to a percentage allowing you to lay pipe or grade driveways at a percent slope. Some models that do grade will allow you to enter the desired slope percent into the keypad, and some dont have that feature. The ones that dont let you enter the grade percentage, you'll have to do the math yourself and then tilt the beam to meet your desired slope.
Theres a lot of rotary lasers to choose from. We generally recommend that you first define the tasks you're going to want to accomplish with your laser. Then start looking at the features you might want, such as; plumb-up beam, plumb-down beam, variable rotation speed or fixed rotation speed, accuracy, detector included or not included, some kits offer "interior" packages and include a ceiling or wall mount bracket, and some kits offer tripods and grade rods included. If you need help selecting a Rotary Construction Laser, please contact us as we'd be glad to help you make sense of the various models. We'll answer your questions, and also promise no sales pitch.
You might consider reading our document
Construction Laser Levels Explained.