18"; Microphone Boom Arm. The Samson MBA18 Microphone Boom Arm is the perfect microphone accessory for any radio, podcast or home studio setup. The telescoping design of the MBA18 provides a maximum horizontal/vertical arm reach of 18";, giving users convenient flexibility with their mic placement. The mic book arm easily attaches to a table or desk via its C-clamp mount, which offers a maximum grip of 2";. In combination with its iron and plastic construction, the MBA18 offers 5/8";-27 mic clip threading that can accommodate any mic weighing up to five pounds.