What is the most common length of sheath used in radial access and why?

There have been studies and the longer sheath, the more sheath in the artery, the more intimal damage it can cause...therefore, use 12cm. But the most important is that it is coated.

Topic: 
Author: 

Bernadette Speiser, RN
Jesse Brown Veterans Administration Medical Center
Chicago, IL

Question: 

What is the most common length of sheath used in radial access and why?