What is the difference between a Solid, Hollow A & Hollow B instrument?

When you purchase instruments the manufacturer should state if they are a Hollow A, Hollow B or a solid. 

If you can't find that information and your instrument is not a solid then please use the details below to determine what type of Hollow you have by measuring the hole size:

 

These snippets were taken from the AS:NZS 4815

To get a copy go to the standards site and search 4815 or 4187 to find the relevant standards for your practice

The key thing to know is what is your Autoclave capable of sterilising. Some autoclaves can only process solids, some solid & Hollow A and some can do any.