AMBIDEXTROUS FIT: Featuring an ambidextrous fit, the SkyFlask can be carried in either hand with or without the thumb loop. ADJUSTABLE HAND STRAP: Adjustable hand strap, cinches down for a precise fit. THUMB LOOP: Soft, padded thumb loop lets you hold the flask in either hand without gripping or squeezing. SPEEDFILL CAP: Leak proof 42mm SpeedFill Cap provides fast refill access at aid stations. LIGHTWEIGHT AND COMPACT: Soft material conforms to your hand and packs away when empty.