Long Sleeve Mock The Sierra Swirl Long Sleeve Mock is the perfect layering piece for any outdoor activity for multiple reasons. The jersey fabric is built for performance while our limited-edition Sierra Swirl print is one of a kind. The purple mist sleeves and zipper harmonize magically with the pattern. This long sleeve athleisure item has long back body darts which will slim your figure and a scoop hem which will prevent any bunch up during your backswing. UPF30 Protection.