Reference: Mirror Tag Guide

Jurassic Park Mirror Tag with instructions

The dimensions are 4.25"x3.25"

Take it to Staples, or Office Depot, have them print it on 2 sheets of regular paper, not photo paper. Have them trim the excess, then glue the 2 piece back to back. Have them laminate it, leaving a 0.25" border (or less), then ask them (or do it yourself with scissors) to round off the very edge of the corners.

Next head to your local hardware store and buy some Brushed Nickel Beaded Chain. Trim the chain down to size (shorter is better), then drill a small hole just big enough for the chain to fit through. The bigger the hole and longer the chain, the more the tag will fly around.

Very easy, very cheap, and looks cool!