By Ashley Mayo

The weather at Royal Birkdale could switch from sunny and warm to a gusting cold rain in an instant. That’s why functional apparel is more important at the Open Championship than any other major, and Jordan Spieth will be ready with serious gear.

Spieth will wear a range of Under Armour’s latest product technologies, including its “reactor” science, which is designed to adapt to various weather elements with water resistant and quick-drying coatings, and its “storm” technology, which is designed to help Spieth play comfortably through even the rainiest conditions. Spieth will also wear polos that have Under Armour’s “threadbone” technology, which is designed to dry fast without clinging or chafing, and the “Spieth One” shoe, which the 23-year-old helped design.

Also new this year, Spieth will rely on Under Armour’s Athlete Recovery Sleepwear, a line of apparel that’s designed to help an athlete’s body rebuild during the sleep cycle.

And for those of you who are interested, here are Spieth’s outfits sans outerwear (main image).