Our diffraction film is perfect for bringing rainbows into your home! Place it in a window that receives DIRECT SUNSHINE and a prism of beautiful colors will brighten your home! Ships in a re-useable tube for safe-keeping. ***THIS FILM DOES NOT HAVE ANY ADHESIVE*** It can be attached to windows using standard tape, but tape may damage the diffraction in areas where the tape contacts the diffraction film, so use it sparingly. 13,500 lines/inch, double-axis diffraction for the best rainbow effects! It can easily be cut into smaller pieces. Perfect for Rooms That Receive Direct Sunlight. Sunlight MUST PASS THROUGH the film to create rainbows. The best effects are achieved with early morning and late afternoon sun. East- and west-facing windows work best. The absolute best effects are achieved where sun from a window is cast onto an opposing wall--the further the wall, the larger the rainbows. CHECK OUT THE AMAZING PICTURES people are posting in their reviews of this product!!! These will give you a good idea of how to maximize the rainbows in your home (as well as giving you the worst examples)! This same material can be used to make lenses for your own paper/cardboard fireworks diffraction glasses. Great Quarantainment! PLEASE NOTE: This material is not appropriate for window privacy applications. It is fairly transparent.