Please note that the stock shield on the Defiant is the Pinlock Ready Max Vision with Brow Vents shield.  If you are looking to replace your shield with the same shield that came on your helmet at the time of purchase, you will find this shield by clicking on "Pinlock System".
Pro Shade System
Standard Shields
Race Shields
Mirrorized Shields
Pinlock System
Dual Pane Shields