If like me you have problems with a pullin' cocker you might consider the gentle leader - I bought one today for a tenner at PAH because I am not getting very far with harnesses (though I have tried the sporn type which gave an improvement but it was still a stop, start walk which was frustrating for Dax and for me).
The gentle leader did everything it said on the packet and we had an enjoyable walk on a loose lead tonight after much bribery and click treating .. am hoping this isn't short lived but it will give me the breathing space to leash train Dax in training sessions and still enjoy nice walks every day without getting pulled all around the town