SKATEBOARDING FIREBIRD TRACK JACKET. UNISEX. ADULT. Skateboarding Firebird Track Jacket (Gender Neutral). The adidas Firebird ADV Track Jacket gets an unexpected update that redefines its aesthetic for modern skateboarding. Using a subtle iridescent plain weave, a slight shine gets added to its classic comfort, cut and fit. Its UNITEFIT sizing structure is created to fit all sizes, genders and forms. . This jacket was made using UNITEFIT — an all-gender fit system that was created with a spectrum of sizes, genders, and forms in mind.