Callahan X REVOLVE Polo Top in Black. - size XS (also in M,S) Callahan X REVOLVE Polo Top in Black. - size XS (also in M,S) 100% cotton. Hand wash cold. Rib knit fabric. Item is not sold as a set. Imported. CAHN-WS14. RC206. Los Angeles based brand Callahan is known for their comfy sweaters and perfect boyfriend fits. Their line is elevated by unique textures, materials, and techniques that give each piece versatility and wearability. Designed for cool girls everywhere, Callahan is inspired by effortlessly easy style.