I've tried using some small things as sounds, but now I've got a good one. I milled down a surgical steel rod that is about 11 inches long. After a thorough cleaning/luring I watched the whole thing as it slid deliciously down my urethra. The ridges I put on it feel amazing when I fuck my dick with it. I was able to get it down past my prostate and it was GOOD! I had my orgasm with the sound still in place resting in the prostate and the orgasm was the strongest I've had in like a year at least