This feature provides a low-noise option for customers or sites with stringent acoustical requirements and where a minimal system footprint is not critical. The acoustical cover option consists of a special front and rear doors that are approximately 250 mm (10 in.) deep and contain acoustical treatment that lowers the noise level of the machine by approximately 7 dB (0.7 B) compared to the slim line doors. This reduction in noise emission levels means that the noise level of a single model system with slim line covers is about the same as the noise level of five model systems with acoustical covers.