2mm Foam Sheets, 11.5 X 4.5 inches, $1.00 each
2mm is available in a huge variety of colors and shades including several new great fishing colors. 2mm is called for in most of the patterns that use foam sheet. It is a common addition to panfish and trout patterns of all types but especially terrestrial patterns. 140 denier thread is about right to crush this down against the hook to secure it. Thicker thread is fine if that is what you want for the rest of the fly.
These colors needed different light to show up right.