Davis Quick Reference Celestial Navigation Card [132] Brand_Safe-T-Alert Multi-layer filter provides a spectral

Multi-layer filter provides a spectral response that closely matches the Erythema Action Spectrum

and corrosion and prolongs the life of any engine

Can be used in conjunction with the E66019 ST69 speed and temperature sensor

Inside Diameter: 35mm - 1

Davis Quick Reference Celestial Navigation Card [132] Brand_Safe-T-Alert Multi-layer filter provides a spectralQuick Reference Celestial Navigation Card A simplified, yet complete Celestial Navigation system. Includes everything you need: sextant use and corrections, star finder for 18 stars, data entry form, and step by step sight reduction and plotting procedures. May be scored and separated; a large portion fits in the sextant case for quick reference, and a small part acts as a waterproof data reduction card.