Knee warmers/arm warmers get tucked into your shorts/shirt sleeves - they are made to be easy to put on and remove and to be small and packable, unlike a pair of tights that once you put on, you are unlikely to want to remove and may be a bit difficult to fit into your pocket. Only a little bit- like an inch or so, gets tucked in - so its not like you need to undress to put them on or take them off.