The 121-115108-01 6.0 to 10.3/4.9 to 8.3 Ultra Long Zoom Lens from Christie is compatible with the company's LW401, LW551i, LWU421, LWU501i, LX501, and LX601i projectors. It provides a 6.0 to 10.3:1 throw ratio when used with the LX501, allowing the distance between the projector and the screen to be approximately 6.0 to 10.3x the width of the projected image. When used with the LX601i, the bulb provides a throw ratio of 4.9 to 8.3:1, allowing the distance between the projector and the screen to approximately 4.9 to 8.3x the width of the projected image.