Yes this is the same picture as the Gen 2 ones because I don’t have a Gen 3. 
This is the Duality Arms Flared Magwell for Gen 3 Vectors. 
The KRISS Vector Gen 3 gives the carbine a wider, funnel-shaped magazine opening that speeds up reloads and reduces fumbles. It integrates cleanly with the Vector’s lower, matching the angular aesthetic while adding just enough outward flare to guide the mag straight in under stress. The design keeps a low profile, adds no bulk to the grip, and improves consistency.
These products are all made right here in The USA!
 
Please note that due to the nature of 3D printing, minor imperfections may be present. However, we stand behind the quality of our products—if it breaks, we’ll send you a replacement, no questions asked.