Urinary Catheters 101: Types of Catheters There are many different types of urinary catheters. This brief introduction gives a brief overview of the basic kinds of urinary catheters along with some images of each, then finishes off by explaining how catheter sizes are measured in French Units along with a conversion table. I hope this video is useful and informative. If you want more information, news, tips, and resources about urinary catheters, visit http://www.catheterguide.com.