Quick Reference Guide(Left) and Data Book 2.0(right)
Data Book 2.0($49.95)
This uses a simplified density altitude-based, color-coded chart to record your rifles' data across a wide spectrum of shooting conditions. It is weatherproof, and can be reused by erasing with alcohol based substances. There is a field expedient density altitude calculator, cold bore shot tracking log, known distance data confirmation pages, range cards, a point of impact shift tracker, and simple hasty hold formulas
Quick Reference Cards($19.95)
This offers quick reference range estimation sheets, checklists for building shooting positions, aids for the observer, and aids for reading wind.
http://www.youtube.com/watch?v=BOEfiAZtlP4
From: Magpul