This replacement 330W NSH mercury arc lamp is user replaceable and will last up to 1500 hours (typical). The benefits of using a NSH lamp in this Christie projector is that is allows for a smaller and lighter projector (because the power supply is smaller and lighter), a cooler running, quieter, and less expensive-to-operate projector (because of the lower wattage) and a longer lamp life (because the stresses on the lamp are reduced).