Feature●Affordable universal clamp●FastClamp Easy Set-Up System●This clamp can be attached to an existing stand pipe that is 15. 9mm to 28. 9mm in diameter. By attaching a L-Rod or cymbal boom arm that is 9mm to 12mm in diameter, you can easily add a cowbell, woodblock, or cymbal to your drum kit.Description This clamp can be attached to an existing stand pipe that is 15. 9mm to 28. 9mm in diameter. By attaching a L-Rod or cymbal boom arm that is 9mm to 12mm in diameter, you can easily add a cowbell, woodblock, or cymbal to your drum kit.