A rubber expansion joint (also known as a rubber bellows) is a flexible pipe connector designed to absorb thermal movement, vibration, and minor misalignment in piping systems. It typically consists of a moulded rubber body with flanged ends, often supplied with stainless steel, carbon steel, or galvanised flanges, and is used in water, seawater, HVAC, industrial process lines, and pump connections to reduce noise, protect equipment from shock loads, and extend the life of the pipeline.