This what we have. Small - rechargable - safety pin
Cheetah 2.5 Mil Rechargable Stun Gun With LED. - Stun Guns by Stun Gun Direct
This similar to what we gave our daughter when she moved into her own home.
Stun Batons
The second one is probably better for walking our dogs but it's heavier and bulkier. The length is what's nice - it keeps who/whatever at a distance from you.
It's too bad we have to result to these precautions and I would only use this as a last resort.