Red LEDs provide a bright red turn signal flash. Each Genesis 4 rear turn signal has a black circuit board with 48 red LEDs and 1156 pigtail bulb base. Plug and play replacement manufactured by Custom Dynamics for OEM rear turn signal bulbs on Harley-Davidson motorcycles with bullet turn signal housing. Custom Dynamics red, smoked or clear motorcycle turn signal lens (sold separately) required for proper installation. OEM lenses are not compatible. SMART Signal Stabilizer (sold separately) is required on 2013-Earlier Harley-Davidson Sportster, 2011-Earlier Dyna, 2010-Earlier Softail, 2013-Earlier Touring and Trikes and all V-Rod models to ensure proper turn signal function and flash speed.