The Nederman Extension Arms are made up of a rectangular steel profile for maximum stability. The Nederman Extension Arms shoud be mounted to a rigid wall or other vertical surface at a minimum mounting height of two meters. EXTENSION ARM - EA 250 The EA 250 is equipped with one swivel and has a length of 8ft. Giving the balance arm a maximum working radius of 20ft. EXTENSION ARM - EA 450 The EA 450 is equipped with two swivels for extra flexibility and has a length of 15ft. Giving the balance arm a maximum working radius of 26 ft.