Marshall Underwater Industries, Inc.

Marshall Underwater Industries, Inc. manufactured and sold standard and custom neoprene molded underwater pluggable connectors capable of being mated submerged in a de-energized condition. Ideal for low voltage applications such as sonar, temperature and current instrumentation, battery packs, cameras and lighting.

Voltage/amperage ratings of 115V/7.5A and 230/15A
Products pressure rated from 10,000 to 20,000 psig.

We have been involved in all facets of this product since 1966. With several unique features of our designs, MUI connectors are molded out of neoprene rubber with a precise interference fit between the contacts and rubber to rubber interface to ensure waterproof integrity. Learn More about Our Story here.

Our Motto and Mission is…

Experience Builds a Better Product™

Marshall underwater pluggable connectors


Phone (503) 899-9644

On June 1st, 2023, Marshall Underwater Industries (MUI) sold its assets. Thank you to our customers for your business over the past 35 years.  This business and its customers meant everything to Bruce!  For future product needs, Taylor Oceanics was the purchaser of MUI’s assets. 

They may be contacted at: or