It comes with 3 different bases. 2 simple rubber rings to ensure an air sealed application, and a vagina-looking thick rubber base to use as a stroker. The rubber seals work very well and create an airtight base allowing the pump to pump fairly quickly. The tube is big enough for trying new things. I put my fleshlight sleeve in the tube and pumped it up. The sensation of that was awesome. It felt like a warm wet vagina was trying to suck everything out of my unit while making it super hard! I've had it for 6 months, and it is still working like the day I bought it. I highly recommend this product.