When you need the power, versatility, and ruggedness of our waterproof Apex headlamp, but you’re looking for a lighter weight option, you need the Apex Pro. The slimmed down Apex Pro was designed with weight conscious adventurers in mind. The Apex Pro is powered by 2 CR123 lithium batteries protected in a highly durable and waterproof housing. Not only lighter in weight, lithium batteries are better suited for cold weather. Built for professionals; perfect for all users.