Features: Round and round and round they go! 24 ultra bright smart LED are arranged in a circle with 3.3" (85mm) outer diameter. The rings are 'chainable' - connect the output pin of one to the input pin of another. Use only one micro-controller pin to control as many as you can chain together! Each LED is addressable as the driver chip is inside the LED. Each one has ~18mA constant current drive so the color will be very consistent even if the voltage varies, and no external choke resistors are required making the design slim. Power the whole thing with 5VDC and you're ready to rock. There is a single data line with a very timing-specific protocol. Since the protocol is very sensitive to timing, it requires a real-time micro-controller such as an AVR, PIC, mbed, etc. It cannot be used with a Linux-based microcomputer or interpreted micro-controller. Our wonderfully-written library supports these pixels! As it requires hand-tuned assembly it is only for AVR cores but others may have ported this chip driver code so please google around. An 8MHz or faster processor is required. Comes as a single ring with 24 individually addressable RGB LEDs assembled and tested. Specifications: LED: 24-bit Inner Diameter: 7cm/2.8in Outer Diameter: 8.5cm/3.3in Weight: 8g(approx.) Package Includes: 1 x LED Ring Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. .