Spectra IV was designed with ease of installation and ease of maintenance in mind. Each dome system consists of three components: a back box, a dome drive, and a lower dome. These three system components are interchangeable with other Spectra IV SL and Spectra IV SE dome systems, making retrofitting and application adjustments simple. Also, dome drives and lower domes can be removed and replaced reducing maintenance time. The Spectra IV SL series is an entry-level Spectra dome designed for those applications which require good quality video and control but not all the features associated with the Spectra IV SE series. This model is available in all standard models, including in-ceiling, surface mount, pendant, environmental in-ceiling and environmental pendant.