The MS CAB CL 01 from Gravity Stands is a clamp that aids in the recording or sound-reinforcement of electric guitar cabinets. This powder-coated aluminum clamp affixes to cabinets that measure between 11.8 to 15.7". For the mic arm itself, it offers an extension length of 9.8".
Once the clamp is mounted, you can place a microphone clip on its 3/8" threaded end, and point your microphone at the speaker. Now you don't need a separate mic stand to mic your guitar amp.