This really is a good idea to wear all year round. It has elastic in two parts which means it fits most hat sizes. On the inside is a sticky rubber that grips onto the hat, to make sure it does not ping off if your head knocks a branch. It does not damage velvet hats.
The fluorescent EN1150 tape is 100% reflective and fluorescent. Wipe clean witha warm soapy cloth.
One size fits most sizes and styles of riding hat. All reflective tape is 2" wide.