You could use an air based or a water based pump. In my experience the water-based is more comfortable. Whichever, you choose make sure that it is built to last. The cheap ones, simply won't hold up. I personally like the Bathmate. I have noticed a definite increase in girth (while not a great amount, 1/4") it is still encouraging to see that it does work. My length has increased 1/8" It takes a month of so to figure how to best use the pump so be patient. You have to tailor the time intervals, rest times and the duration of the pumping session for your body. Follow the guideline from the manufacturer which should give a good starting point. Don't get discouraged, since it takes time to see results.