Projector screens come in a multitude of styles and models, and arrays of options.
Electric screens are wall or ceiling mountable screens that use electric motors to power the screen "up and down". Fixed screens are screens that are mounted to frames, very much like pictures or paintings. Manual screens are operated by hand to roll up and down. Lastly, portable screens are screens that can be placed on the floor and can fold into a relatively small package for portability.
Screens are manufactured in three main aspect ratios: square, 4:3 (1.333:1) and 16:9 (1.78:1). Square screens (1:1) are used primarily in business applications.4:3 screens are used more frequently as they match the aspect ratios of computers and standard definition television. 16:9 screens are almost exclusively used for home theater and HDTV viewing.