Welcome to ACMOC Wholland, you have found the right place for finding information for your Caterpillar equipment.
I suggest you change your profile to allow your town or your general location to show. This will help others to help you without having to ask your location.
My parts books for the blades used on your D7 17A do not show any back-up rippers. I believe all back-up rippers for your tractor are either aftermarket or fabricated. Pictures would be a big help. Someone here will probably be able to identify the brand and help you.
Craig