e3 Diagnostics Raleigh was initially 1 of only 2 locations in the U.S. that operated as a direct sales representative for Grason Stadler (GSI). Over the years, we have become the leading distributor of audiology equipment in the Carolinas. Eventually, we supplemented our line of GSI products with instruments from other world-leading manufacturers, helping us evolve into the multi-line sales, service, and support business our customers have relied on for years.