AGV GT2 Pinlock Insert Fits K1| K5 | K3-SV Helmets From  £28.99

Picked this up for my AGV K3 SV for a motorcycle trip in Alaska. I had some mild fogging after riding for 2 hours in the rain but it was still very minor. Without the insert, my visor would've been completely fogged up (the edge below and above the insert was). Overall, very happy with the purchase and I'll be using it for any wet weather riding from now on. Highly recommended!