look for somthing called "x-marker"
it lets out a loud... VERY loud noise. it coats the attacker with a horrible smell, fires a blue foam, that dyes the skin blue AND has UV in the dye, so that an attacker can be easily spotted should the police be needed to resolve the situation.
http://www.stoppa.co.uk/acatalog/copy_of_Click_Her e_for_X_Marker_Self_Defence_Spray.html
hope
this helps!!!