Replacement brush for our WC set is quite ok, but I must say this, they dissolve always something on the screw by itself using the. "For this, I can give a simple tip" Wrap and screw something sealing tape from Plumbing to the thread, holds great and you can change the brush again at any time. The price of course is for a brush head already pretty high, I find, but that's when one is dependent on certain models, others are not fit for the thread. Oh, the delivery was very fast, excellent and reliable. With the service of Amazon, I am very satisfied.