Police-issue OC works well. I have had several large, viscious dogs (including a pit bull and a Rot) turn tail when hit in the eyes with it.
Member: Orange Gunsite Family, NRA--Life, Varmint Hunters' Assn., ARTCA, American Legion, & South Cuyahoga Sportsmen's Assn.
Caveat Emptor: Cavery Grips from Clayton, NC. He is a ripoff