Hoya HD Digital Protector 
Hardened optical glass that has 4 times the breaking strength in ANSI standardized testing (ANSI Z80.3 : 2001) where a steel balls of varying size and weight were dropped from a height of 50 inches onto the glass. 
8-layer multi-coating yields an average light transmission rate of 99.35% between 400 and 700nm (visible spectrum). These coatings greatly reduce reflections off the surface of the glass allowing you to capture more light in your photos. 
As with all HOYA multi-coatings,HD HMC is applied in a furnace at high heat, bonding the coating to the surface of the glass. This process is called "hard coating" and it is very durable. The chemistry of the top layer is formulated not just to be more durable but to be resistant to oil stains. This means that finger prints and other oils are much easier to remove.

HD GLASS

• Ultra Clear High Transparency Optical Glass

• Chemically Enhanced Optical Glass is 4x Stronger

HD COATING

• 16-layer (both sides) Anti-Reflective Multi-Coating

• Water & Oil Repellent, Scratch & Stain Resistant

HD FRAME

• Wide-Angle Lens Compatible Ultra Thin Frame

• Glass Mounted with High Pressure Press Technology

PROTECT YOUR VALUED LENSES

This is the ultimate in clear filters. It will not affect the color balance or performance of your lenses in the slightest. However, constant use will protect your valued lenses from expensive front element damage which could be caused by dirt, knocks or scratches.