FAQ - Frequently Asked Questions - Knowledge Base
Where I can purchase the correct 3-pin to 4-pin converter for my fan?
The Molex number for the required 3-pin female plug are as follows: 
Housing 5102-03 
Terminal 5103 
For your reference, the part we use in the Digital Doc 5 is: 
Housing 5240-03 
Terminal 5241 
To purchase those plugs or a finished converter, please check your local computer stores or some online stores, thanks.
 ODM for Thunderbolt Storage Solutions
ODM for Thunderbolt Storage Solutions