Force "Twinkl" waterproof tail light. It has 2 led diodes and a powerful 0.5 Watt led. It has two modes, one pulsating and one fixed and is recommended for use within the city. It has a base for mounting on a pole mount with a diameter of 25.4 to 31.6mm and weighs 66g including the base. The package includes 2 AAA batteries and clips for attaching to clothing, bag and belt.