reflective material; safety reflector
Refers to material that reflects light, commonly used in safety vests, traffic signs, and bicycle reflectors.
夜間のジョギングには反射材の付いたウェアがおすすめです。
For jogging at night, clothing with reflective material is recommended.
Attaching a reflector to your bicycle improves visibility at night.
Compound of 反射 (reflection) and 材 (material).