SensGard makes lightweight, non-electronic hearing protection built around patented Zwislocki Ear Muffler (ZEM) acoustic-chamber technology, redirecting harmful sound while preserving speech and awareness. The company’s work grew from auditory scientist Dr. Jozef Zwislocki’s research at Harvard, with the SG-31 later receiving the 2009 Frost & Sullivan North American Product Innovation Award. SensGard products are made in the USA as a compact alternative to foam plugs and bulky earmuffs.