Pratt Urethral 11 Inch Sounds This set of 11 inch probes is very similar to our 8 inch set. The sounds are made of chrome-plated brass. Each probe in the series is slightly larger than the one before", and slightly larger on one end than on the other, for a total of 16 graduated sizes. The original intended medical use for these probes was to dilate the cervix, but they were also used to clear blockages in the urethra. The tubes are rounded at each end, and they come in a high-quality," zippered black or red leather case velvet lining inside. Click Here To Order