NEC Lens Unit. The NEC NP18ZL 1.73-2.27:1 Standard Throw Zoom Lens from NEC is one of six optional lenses available (in addition to the standard lens) for the NEC NP-PX750U projector. It is designed to support a variety of specific installation environments, such as conference rooms, halls and exhibitions. The lens is easily installed by end users and doesn't require any special tools.