http://www.coldsteel.com/Product/SAFE.20_KEEPER.20_SERIES/SAFE_KEEPER_SERIES.aspx
With mother's day coming up I wanted to bring something up. I used to work at Merlo's Cutlery, a now-closed knife store. Though we made these sorts of sales all the time, whenever a holiday would come around people (particularly men) would come in saying that they wanted to buy a woman in their life a knife for protection. Every time I (or another associate) would explain the following to them:
Do not carry a knife for protection unless you are trained in using one. In an incident, an stronger or quicker attacker can take your knife and use it against you. This can also be true of pepper spray. Instead, look into punch knives/daggers. These have a T-shaped handle that fits between your fingers (the same way that some people hold their keys for protection). When in danger, aim for your attacker's main arteries (the inner thigh is a particularly good spot for those of us on the shorter side).
I am including a link to a knife of this sort from one of the better companies: Cold Steel. The biggest draw back with these is the case which can occasionally come loose, and, when de-sheathing you want to be careful that your thumb isn't too low or you'll rake it along the edge when you pull it out.
Please, pass this information on. It may just end up helping someone out.