*Provides high visibility in all light conditions. *Fluorescent yellow fabric, as well as reflective tape on either side of the jacket, ensures visibility in any environment during the day. *The addition of a unique and innovative technology called 'Vizlite DT', ensures that a dog can be easily seen, even in complete darkness. *Vizlite DT absorbs light from any UV source (the sun or a bulb) and works like a battery to store the absorbed light. *When there is no more light to absorb (in darkness), the stored energy is emitted as a bright glow which remains visible to the human eye for up to 8 hours thereafter. *Showerproof. *For correct size, measure length of back from base of neck to root of tail.