If the lamp dies during a presentation or teaching session this would be inconvenient and disruptive. Twin lamp slide projectors have two lamps installed with only one lamp being used at a time. If one lamp dies then the second lamp takes over.
Slide projectors are supplied as a 'basic body', which means the slide projector comes only with a lamp and a mains lead. The lens and a slide tray are not included. Lenses are in general compatible across all models therefore can be used interchangeably.
Infra-red remote controls with a range of 20-25 metres allows you to find a slide, advance or reverse, adjust the focus of the image, or in the case of AF projectors, operate the autofocus mechanism.