The alloy baton is light weight and fits neatly vertically inside my small handlebar bag. Illegal in some states. Works on any dog, every time. Just a tap does the trick. Don't swing it as you may lose control of the bike. Probably works on human pests too, although I have no experience. No one gains resistance to a wrinkled skull.
http://www.buy.com/pr/product.aspx?s...lerid=31337309