These adapters are good value for money, the material has a rubbery feel and has a little give which helps with the grip to the suction hose. I had to get a bit creative to create an attachment that worked with my rotary sander that required the largest diameter, the same as the vacuum cleaner, which meant cutting the smaller parts of two units and creating an attachment with the larger end on both sides. The only downside is that the smaller sides don't slide into each other so I had to make a "V" shaped incision on one unit to be able to make it fit inside the other unit and then seal it with gaffer tape.