These Dittel Urethral Sounds are about 10.5" long, with a flat end to make handling them easy.  

Made out of stainless steel, they are very heavy solid sounds in French Sizes from 18 to 32.  French sizes are the distance around the shaft (circumference) in millimeters. This distance can then be converted into the approximate diameter of the sound in millimeters by dividing the French Size by 3.  So the diameters of these sounds would be 6 mm to 10.7 mm.

Sold in a set of eight, they come in a handy velvet-lined zippered case for easy transport and storage.