This company now offers its Sound Vault Housing as an option on the company's QEI fan. The option provides an enclosure lined with two inches of sound-attenuating insulation, integral isolators, and flexible connections to lock in radiated sound and minimize vibration transmission. The fan is ideal for applications where noise levels are critical, such as office buildings, libraries, or educational facilities. Greenheck, P.O. Box 410, Schofield, WI 54476-0410; (715) 359-6171; fax (715) 355-2399.