The Chuckit! Pro LX Fetch Ball utilizes a highly reflective lens technology to enable you to Find The Ball Fast! There is an integrated LED flashlight right inside the launcher handle. Simply shine the LED at the reflective lens inside the ball and you will find your ball at up to 50+ yards away - never lose a ball in the dark again! Ball also contains Max Glow rubber technology that absorbs light quickly and glows for up to 30 minutes of playtime after dark. Medium size works with Chuckit! Pro LX Launchers.