21 g Taulman TCTPE Nylon (other materials should also work but they should be flexible) 30" x 3/8" braid elastic (76 cm x 1 cm) 8.5 x 14 inch transparency. US Standard 3 hole punch A sweat band can be made by sewing a 3.5 inch piece of fabric centered on a 1.5 x 6 inch piece of fabric. The sweat band lays over the top of the head strap. For the lens support version, There are small buttons that need to be added to the assembly vs the attached ones in the previous design. They are sized to be attached with #2 self tapping screws.