A Collectors Guide For Radio Antenna Insulators on CD. Uses the flipbook format and is very easy to use. The CD contains over 300 color photos of common, unusual, and rare antenna strains. 256 different strains are catalogued. Glass is numbered as GS-001 and up, porcelain is PS-001 and up. Rarity and value are rated on a scale of 1 to 5. Mac compatible. 18 dollars for ICONer's gets it shipped anywhere on the planet. Thank you and happy T'day.