The prtdiag command is very usefull tool for checking your hardware configuration. Based on the output you can tell what is inside your SUN box without opening it. This is also handy when you are dealing with SUN support.
If your SUN box has Solaris 10 (SPARC or x86) prtdiag would be located at the following path
If you are using older version of the Solaris you can find the prtdiag command in slightly different path
# /usr/platform/`uname -i`/sbin/prtdiag