Excellent for deep insertion - flexible enough to follow the curves, but stiff and thick enough that there's no risk that it will fold over on itself, which has happened to me with a thinner colon tube.
Great for using on your own or with a buddy. Nice and smooth for easy entry, and a good handle to help maneuver it into just the right spots. Comes in 3 sizes, so no matter how experienced the hole is, you'll be able to give the prostate a good beating.