Anyone who has ever built their own windscreen has, at some point, taken a pause to consider the following: Where should I put the ventilation holes? How many should there be? How big should I make them? It's a delicate balance. To many holes and you lose wind protection. Too few and you suffocate your stove. Check out this design...you'll get the idea.
The windscreens come in 3 sizes and you can easily trim them to size: Here are the available heights and their respective weights:
4" 1.1 oz. (31 grams)
6" 1.6 oz. (46 grams)
8" 1.9 oz. (54 grams)
The one shown in the video was a 4" Vari-Vent that seemed to fit the MSR Titan Kettle perfectly. Click here for more info. Also, here's a cool page with tips & tricks for using the Vari-Vent.