The Specialized Flash Headlight/ Taillight Combo gives you everything you need to be seen—day or night. It features up to 70 lumens in the front & 20 lumens in the rear, & the versatility of four light modes, ranging from steady & strong to flashing & brilliant. The flexible mounting system works with handlebar & seatposts from 22.2mm up to 35mm in diameter, as well as most seatstays, helmets, & saddlebags. Increase your visibility with the Flash Headlight/ Taillight Combo. Features Headlight: 20- to 70-lumen output. Headlight: 2 hours to 24 hours runtime. Tail light: 5- to 20-lumen output. Tail light: 2 hours to 20 hours runtime. Mode: Output Four headlight modes Steady: 55 lumens Power Flash: 70 lumens Disco Flash: 55 lumens Eco Flash: 20 lumens Four taillight modes Steady: 10 lumens Power Flash: 20 lumens Disco Flash: 14 lumens Eco Flash: 5 lumens