ebm-papst Inc.
FlowGrid's open grill design straightens airflow to minimize turbulence before the air hits the axial or centrifugal impeller blades, which according to the company has been proven in certain applications to reduce overall sound pressure levels by as much as 3.9 dB(A), and blade-passing frequencies by up to 16 decibels.
SC Johnson Professional: Alcare Extra with OPTIDOSE
Horton Automatics: BH Slider
Kimball International: Shore
Protimeter: Aquant
Sensaphone: Sentinel PRO