The Gray Sheets, International Designations and Chemical Composition Limits for Aluminum Hardeners (issued August 2025, superseding December 2018), form part of the Registration Record Series. The record gives the registered designations and chemical composition limits for aluminum hardener alloys, with footnotes, and includes a table of color codes for aluminum hardeners together with color codes listed by designation and by alternate designation. The color coding allows hardeners to be identified visually in the foundry, while the composition limits support purchasing and verification of these master alloys.