How to measure head circumference:your head size :Bring a string ,Then go around your head,1 cm above the eyebrow, well horizontal.Keep the measurement using your finger.Measure the length obtained, which be your head size in cm. Reflective design: the plush reflective beanie is designed in semicircle shape with reflective stripe to increase conspicuity and visibility, so other drivers and workers can easily notice you, which can efficiently avoid traffic or work accidents and people's safety, and is Perfect for construction and work clothing Comfortable material: the high visibility beanie is made of plush material, soft and comfortable to wear, can efficiently absorb sweat and keep your head warm in winter and cold weather; It's also and flexible, 't bring much burden or pressure when you are wearing them Proper size: the reflective winter hat is stretchy enough to provide proper coverage of your ears and head, suitable for most head sizes and shapes, and you not feel too tight or loose, giving you a cozy wearing experience Wide applications: the safety beanies are suitable for men, women, workers, sportsmen and so on, can be widely applied to a variety of outdoor activities, such as construction, running, cycling, hiking, skiing, camping, repairing, walking the dog, jogging and more Hat Size:About 20cm long and 20cm wide (56-58 cm)for women/men/6 years old to children adolescents all can use. Colour:Fluorescent Yellow Material:95% Acrylic Fiber, 5% Reflective Yarn Package Contents: 1 x Hats Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.