Create a Custom Boom Arm. Ideal for Small to Medium Lights and Speakers. 48mm Receiver. Pre-Drilled 1m Tube Available SeparatelyReceiver: 48mm Tube Diameter: 48-51mm. The Scaff Boom Arm enables you to create a Boom Arm to suit your needs. Ideal for rigging small/medium moving lights- speakers- PA’s etc. Featuring a 48mm receiver- lengths of 48.3mm Aluminium Barrel or Galvanised Scaff Tube can be cut and drilled to suit. A pre-drilled 1.0m length of Aluminium Barrel which can be cut down to your requirements is available as a separate item.. lighting clamp-boom arm-scaff clamp