C9 Commercial Christmas Lights, heavy duty 18AWG SPT-1 outdoor wire thicker than 20AWG SPT-1, higher safety performance and lifespan. End to end connection, connect up to 30 sets, one bulb goes out will not affect others lighting. LED bulbs feature a reflective core design for superior optics and brilliant light, polycarbonate lenses for shatter resistance, and an average life span of 50,000 hours. they're tougher than the average bulbs, they are shatter-resistant, fade-resistant and energy efficient.