PEX Lens Technology is featured in 100% of HammerHead Spearguns dive masks. APEX Technology increases light transmission over standard tempered glass by over 13%. That means you should see 13% πr2 more lobsters, octopus, or fish! APEX lenses are manufactured in a process that eliminates iron oxide impurities for 13% increase in light transmission over standard tempered glass. Advanced technical lens coatings are then applied to the APEX glass for the most extreme of dive applications.