This Dog Safety Collar comes with an extremely durable & waterproof LED Electronic Light. It consists of a reflective 2.5 cm wide nylon collar with an attached battery housing. The light has two settings blinking or static light. Your dog will be visible up to 300 meters away. The light comes standards with traditional CR 2032 3V batteries that last for Approx. 150 hours. The batteries are easily changeable with a Phillips screw driver. Operating the Light Static Press the indicated button for 2 seconds Flashing Press the indicated button for 2 seconds Deactivate Press the indicated button once more for 2 seconds Nite Dawg LED Dog Collar is available in different sizes Size S 254-33 cm Size M 33-46 cm Size L 46-69 cm Tips for adjusting the collar Because the LED Dog Collar is somewhat more compact than other traditional nylon collars it is important to keep in mind Pull the collar approx. 5cm from bottom to top through the first adjustment clip rotate the collar & pull it as far as possible from top to bottom through the second adjustment clip. What´s this?