This is the size 6 Onetigris muzzle. You can buy on Amazon.com
Once your dog is conditioned to wear the muzzle you can take your dog anywhere dogs are allowed in public.
Your dog should be able to go beyond doubt anywhere in public without a muzzle as well. So get your dog socialised first.
You can Defend yourself and your dog can Defend itself from attack.
With your dog trained to wear a muzzle you and your dog are complying with the law.