<prompt> Which of the following catheter materials is most suited for long term is usedLatexSiliconeRubberPol yurathane  <response>: Ans. is b i.e., Silicone Catheters made of silicone are, in general better tolerated over the long-term than those made of materials like latex and polyurathane. - Cambell, 8e Also remember Catheter size is usually measured in French fr it refers to the outside circumference of the catheter, not the luminal diameter. Thus a 20 fr catheter may have different luminal size for urinary drainage, depending on the type of material used for construction and the number of lumens within the catheter. 1 Fr 0.33 nun in diameter thus 3 Fr 1 mm in diameter thus a 21 Fr catheter would be 7 mm in diameter 