Related Clues:
- Longtime sponsor of racing's #43 car
- Eng. conditioner
- Auto additive with a red oval logo
- Longtime auto racing sponsor
- Additive sold at AutoZone
- Part of the Armored AutoGroup
- Fan mail encl
- Lucas Oil competitor
- Fuel additive letters
- Gas additive letters
- "The Racer's Edge" Indy sponsor
- RSVP encl
- Enclosure to an ed
- Return mail requirement (Abbr.)
- Common Nascar letters