Good advice so far, SAP gloves would not be a wise investment for self defense purposes. I've never known anyone to use them, most of the people I know wear gloves such as these:

https://secure.usstandardissue.com/P...ail.cfm?id=117
http://www.wileyx.com/EcommSuite/Pro...temCode=G4002X

Durable, lightweight, but with a molded knuckle protector that works wonders for physical contact.