I'd happily pay €5 each for these (bought 3) but still satisfied. They are made of durable rubber that never needs replacing and can be adjusted to fit 4 different tube sizes. I would definitely buy them again. For combining the suction power of 3 vacuum cleaners when cutting plaster and plastered walls with an angle grinder. Crazy Dust. It's a tiny job, but if this thing works, it will pay for itself tenfold. Wish me luck.