Steel tube combination for use in subwoofers with flange adapter. The height is fixed with a safety hook and secured by a clamping screw for a vibration-free and firm fit. The slim design of the clamp allows space-saving transport and ensures a stylish appearance. The usable height is between 39.566 and 59.251" and is adjusted in 5 steps of 3.937". Integrated on both sides is a patented expanding mandrel with quick-release fastener, which ensures a tight fit of the subwoofer and the satellite speaker. The plastic expanding splints also ensure a vibration-free connection between the speaker and the tube.