I bought it, because I broke an original one, after a few years of using :-) This parts are a few millimeters smaller in diameter if I compared it with an old one what I have from a company Stairwile. I make it bigger with using a hairdryer :-) If you overheat it, you can a little bit transform :-) just few minutes of work and it is done! The screws are in a good Quality too! If you have an old model (in past there was only a Stairwile on the market with this small trussing), than, there is no afraid that it doesn't fit on! Good product!