Magpul Industries Core™ Quick Reference Rifle Cards The Magpul Core Precision Rifle Quick Reference Cards offer the shooter a comprehensive overview of the fundamentals of marksmanship, quick reference range estimation sheets, checklists for building shooting positions, aids for the observer, and aids for reading wind. Using the same density altitude system and rugged, all-weather, erasable material as the Precision Rifle Data Book, the Quick Reference Cards offer streamlined access to your rifles' elevation and wind data. Intended for use as a medium to transfer data for a given rifle from the Precision Rifle Data Book to these cards for use in the field. Conveniently sized for use in an arm board, your data will always be within reach. Ring not included. Features: - True all-weather, semi rigid writing surface - Recorded material is erasable with alcohol - Mil based range estimation calculator - Marksmanship fundamentals overview and Shooter/Observer checklists - KD Data sheets from -5000 to 16,700 feet DA - Wind Cues - Reticle Hold worksheet for BDC based reticles - 3 1/8" H x 5 1/8" W