You don't have to buy the LED mounting rings separately. This set contains 20 plastic LED mounting rings that allow you to complete the project easier. Super bright, luminous intensity 6000-8000 mcd, simply connect to 12 V, excellent product. Easy to use, you just need to connect the positive and negative wires to your battery or power supply. Low power consumption and stable performance, long service life. Perfect for DIY, hobby lighting, boat, car, industry, camera, toys, and costume design etc. Highly recommended for hobbyists. Specification: 20 cm LEDs with 20 cm cable DC 12 V: Colour: As shown. Diameter: 3 mm Opening angle: 25 Cable length: 20 cm Operating temperature: -25 to 85 C. Operating voltage: 5 - 12 V DC. Current consumption: 5 - 25 mA. Brightness: 10000 - 12000mcd Wavelength: 3000-3500nm Service life: approx. 100,000 hours.