All GlasMasters boxes are made using polymer concrete in combination with fiberglass to provide a high strength, lightweight enclosure.

Polymer Concrete is a mixture of thermoset resin, aggregates and fiberglass reinforcement. 

Polymer Concrete is much stronger than traditional concrete with a fraction of the weight. Unlike traditional precast concrete, polymer concrete will not absorb water and become brittle, which has been a major problem with enclosures in the past.

Fiberglass is material made by applying polyester resin and catalyst to a fiberglass reinforcing mat. The result is a very strong, durable material that will not undergo plastic deformation. Over the years, many plastic enclosures made from high-density polyethylene have been used. These plastic enclosures are often much more flexible than fiberglass and deform far more than allowable under current industry standards. This often leads to a crushed meter or a cave-in which could possibly expose dangerous electrical wiring. Plastic is also highly susceptible to ultraviolet rays (UV) from direct sunlight.