Sisyama Neoprene Weight Loss Sauna Sweat Hot Long/Short Sleeves Shirt Top Slimming Suit Thumb Hole Workout Exercise Long sleeves shirt is designed with THUMB HOLEs to prevent scrunching of sleeves during your workout. REVERSIBLE short sleeves shirt has vibrant color on one side and black on the other. Made with flexilble Neoprene fabric that causes you to sweat. MESH UNDER ARM material provides ventilation and comfort. Speed up metabolism, burn more calories to maximize the effectiveness of your workout. Model is approximately 5'7" and wears a size S. Please order one size down if you are under 5'4" and one size up if you are over 5'10". We use real people instead of modeling agency aiming for the best sizing reference. If you don't find our size chart accurate, please email us so we could better serve your needs. THANKS!