Black. Dark lens. With an overall length of 14mm; a metal housing diameter of 10mm (1cm) and lens diameter of just 7.8mm the Spot RB is an ultra small taillight that re-defines miniature. Easy to overlook in traffic; you”d say; but the High Output power LED in combination with the special Extranz Extreme Optical Transparency technology actually gives it a colossal light output; when taking in account its tiny dimensions. High quality and ECE compliant so fully street legal. This is The One for those that like a taillight not just small but virtually invisible on a bike; until activated. With M5 x 6.5mm threads.- ECE-approved for rear use – EXtranzr – Extreme Optical Transparency Technology – Kellermann HighPower LED Technology – Longlife Protection Guardr; IC operated; 330 kHz- High quality metal housing – Suitable for 12 volt DC applications – M5x0.5×6.5 threaded – Dimensions: Length 14mm; max. diameter 10mm; lens diameter 7;8mm – European design protection Note: See turn signal section for style & size matching Spot turn signals and position lights.