Amazon.com - ArtToFrames Floating Acrylic Frame for Pictures Up To 18x24 inches (Full Frame is 22x28) with Black Standoff Wall Mount Hardware, Acrylic-109-18x24-82
Non-Glare Acrylic Replacement for 18x24 Picture Frame, Replacement Plexiglass for 18x24 Photo - Walmart.com
Amazon.com - Alpina Clear Acrylic Wall Mount Floating Frame for 18 x 24 - Outside Dimension 21 x 27 Made in the USA
Amazon.com - Craig Frames 18x24 Inch Acrylic Glazing for Picture Frame Poster Frame
Contemporary Picture Frame for 18x24" Photos or Posters | UV Grade | High Quality Frames – Wexel Art