12 x 18 Paper Size, Dimensions and Format from the Common US Press Sheet Series which can be found in mm, cm, m, inches, picas, pixels and points.
Printing at 11×17 or 12×18
Hammermill Printer Paper, Premium Color 32 lb Copy
ISO Paper Size Reference Poster, Common Paper Envelope Sizes
Hammermill® Premium Color Copy Print Paper, 100 Bright, 28lb, 12 x
Printing at 11×17 or 12×18
Paper size - Wikipedia
US Standard Paper Sizes for Printing & Framing - Shanty Town Design
A Beginner's Dive into Ring-Bound Planners: Part 2 - Planner Sizes
Digital Board White ITC Digi Art Paper, For Printing, Size
Paper Sizes Explained
A12 Paper Dimensions & Drawings
American paper sizes. Letter and Legal paper sizes.
Paper Sizes Explained
Paper size - Wikipedia
Plain Digital Printing Paper, Size/Dimension: 12 X 18 Inch, GSM