I have these endpins fitted to both my double basses and they really help providing grip on slippery surfaces, for example playing in the reception area at weddings on a marble floor. They are very robust and have lasted much longer than the standard rubber grip fitted to most endpins, which I've found to split very easy with constant use. The only drawback is that, despite tightening the screws with pliers, they still have a tendancy to come lose, so I always check them and give them a tweak before a gig. Other than that, this is an excellent well designed product.