Node 3 consists of a pressurised cylindrical hull 4.5 m in diameter with a shallow conical section enclosing each end. It is almost 7 m long and will weigh together with the Cupola over 13.5 tonnes at launch. The pressurised shell of Node 3 is constructed from aluminium alloys. This is covered with a multi-layer insulation blanket for thermal stability and around 75 sections of panelling to act as a protective shield against bombardment from space debris. This panelling is also constructed of an aluminium alloy together with a layer of Kevlar and Nextel. Internal and external secondary structures are used to support the installation of equipment, piping and electrical harnesses. Two water loops (respectively low-temperature and moderate-temperature loops) allow the rejection of the heat generated inside the element to the ISS ammonia lines by means of two heat exchangers mounted on the external side of one end cone.