The K&M 21105 Microphone Boom Counterweight is used for heavy microphones. This accessory fits all one-piece K&M boom arms with 3/8" thread connector or tube diameter of 15 mm. It can be easily mounted.
The main features of the K&M 21105 Microphone Boom Counterweight include:
Actually using this to weigh down a mic stand, so placed vertically as shown in the photo above. Although not critical for this application, the 18mm long locking bolt is not long enough to project into the hole and therefore cannot fix the weight in place. So, the counter-weight does its basic job, but marked down for failing to lock in place.
I was sick of all my large diaphragm condenser mics causing the mic stands to lose position due to mic weight - this simple counter weight has resolved that problem for good. Easy to install. Very satisfied.