Barnes & Jones cage units contain all of the working parts of a thermostatic steam trap, including the seat, within a stainless steel housing. Cage units are one-piece, stand-alone, fully-removable units. This allows for removal and testing of the element outside of the original trap body. No special tools needed for installation. Cage unit are available for a wide variety of makes, styles, and sizes of thermostatic steam traps for low, medium, and high pressure service.