Nicely thought out, but basically unusable, suitable for use only after previous modification of the clamping part, when you disassemble it, I haven't had something so messed up in my hand for a long time. I use the Seydel Gecko harmonic holder, where the design and processing are flawless. The need arose from But I definitely don't say that I appreciate the manufacturer's efforts, you as a store are out of the question. Thank you Vladimír V.