what do you guys think of this?

[WiNgS]

http://gymratz.co.uk/weight-training...nt/item189.htm

good for building mass on the kneck?

[Iron Warrior]

It looks solid bro, but I just put a a thick towel on my forehead, put a 45 plate on top and do what I call "neck flexion", I then put the towel on the back of my skull, have my training partner hold the weight and do "neck extension". It saves me the money since my gym doesn't have neck machines