http://www.sonicelectronix.com/item_3624_Directed+508D.htmlwhats it do. i might buy it. i have a viper 791XV
if someone goes up to ur car without touchin it, it give a warning chirp. if they get gloser the alarm goes off. they are very usefull unless u live in an apt complexwhats it do. i might buy it. i have a viper 791XV