It is a slender tube, typically made of rubber or PVC, designed to deliver liquid along with enema pot during an enema procedure  Sizes are indicated by numbers (e.g., size 10, size 12) The picture shown above is size 10 which is normally suitable for children. Size 12 is for adults. The higher numbers denote larger diameters. These catheters can be purchased individually or they are a part of full enema set and supplied accordingly.