The tool for Scubapro D-series second stage will open the big black and small silver nut located on the outside of the second-stage regulator body of the Scubapro D300, D350, and D400.
 
The Scubapro D series tool is precision machined from white acetal with a stainless steel grip and hardened stainless steel pins.
 
GTIN: 8720828266366