A 5-line 4D 360 rotary laser level is a professional-grade precision tool designed to project a complete layout of horizontal and vertical lines across an entire room. While "4D" typically refers to models with 16 lines (four 360° planes), many versatile "5-line" 3D/4D machines are popular in India for providing high-visibility green beams that are up to four times brighter than traditional red lasers.