Water equivalent material within 1.0% for photons, and is free of contaminants and air. Slabs from this unique material are exceptionally strong and will not stick together when stacked or stored. Not affected by changes in temperature or humidity and can be used for electrons.

In slabs that are at least 2 cm thick, cavities are available to accommodate parallel plate ion chambers or thimble type ion chambers. Instead of having multiple slabs for each thimble type ion chamber, a single ion chamber slab is used with interchangeable ion chamber plugs.