The material used for this is printable transparency sheets commonly used for silk screen work. You can also use non-printable plastic by printing the design on a piece of paper and tracing on to the plastic sheet.

Download the files SnapShield-band.pdf and SnapShield-Shield.pdf from the files section.
Print one band sheet (6 bands per sheet).
Print six shield sheets.

Using scissors or a paper cutter, cut apart the 6 bands on the long solid black lines.

Using a sharp hole punch, punch all circles located on the prints. 

If you have a 3-hole punch, you can punch the band in the following steps:

1. Align the band in the 3-hole punch in one direction, punch holes.
2. Flip the band to the other side and use the 3 hole punch again. The band is sized so that a 3-hole punch will correctly locate the hole pairs. 
3. Again insert the band into the 3-hole punch, but slide it laterally 1.5" from the end of the punch to create the offset holes.
4. Repeat step 3 for each of the 4 corners. You will end up with 6 holes in the center of the band that are not used.

On the Head Bands, carefully cut all of the solid black lines and remove the portions with the word "Remove."

At the end of each band, fold the band on the center of the "V" and cut on the fold to form the strap slot. Bend back flat.

On the side of each Shield, fold horizontally and cut the black line to make a slit on the edge. The top end of the slit is important, but the bottom end is not. The top end of the slit will provide tension to prevent the shield from flipping up during use.

Curl the end of the Band and insert through one of the side holes on the Shield.
Curl the opposite end of the band and insert through the other side hole in the Shield.

Cut the rubber band and tie an overhand knot in each end.

Bend the end of the Forehead Band horizontally to get the V slit to open up enough to insert a knotted end of the rubber band. Bend it the other way and flatten, then pull gently on the rubber band to seat it on the outside of the V-slit.

Each Shield is now assembled for packing and shipping.

To use the SnapShield, simply grip the shield near one of the outer holes, feed the band through the shield slit, and pull the band through the hole until the arrow shape snaps in to place. Repeat on the other side. Pass the free end of the rubber band through the opposite V-slit and it is ready to wear!