I have a lot of lightweight Chinese made boom microphone stands. I bought some training weights and ankle weights from my local sports goods store. Ankle weights have velcro straps so you can strap them at the back of the boom stand. 500 grams works beautifully for my sennheiser 421's. 0.75-1 kg is ideal for shure sm7. You can also place training weights at the base of the mic stand using the hole in the middle. This works well for heavy condensers. A piece of foam between the base and the weight destroys all possibility of rattle and noise. For tenth of the price you can have sturdier stands than the K&M's. They don't look bad either.