Our base boxes can be 55mm, 65mm, 85mm or 120mm deep. 85mm and 120mm are more flexible and give most plug top and wiring space. See also Downloads /Floor box chooserLow profile junction box enclosures are available in a wide variety of sizes and styles from Polycase. We Offer Custom. Single-Gang, Shallow Box with Vertical Side Bracket for New Construction Applications. Ideal for limited depth applications. The purchase of Global Recycled Standard (GRS) certified. They are designed and manufactured to be installed in extreme environments and offer a high degree of modularity to meet a wide range of applications. - Available with a porthole or.