Many testing instruments are proprietary, and some may not be available without a fee.  These databases provide you with reviews or other information about the instruments, and sometimes (but not always) the instruments themselves.  Look for contact information for the author and/or copyright holder of the instrument if you would like full access.

For more information, see Tests and Measurements.

Databases containing information about testing instruments. 

Note: Many instruments are proprietary, and some may not be available without a fee.  These databases may only provide you with reviews and information about the instruments, not the instruments themselves.  Look for contact information for the author and/or copyright holder of the instrument if you would like full access.