The SemiLED UV LED uses proprietary MvpLED technology, a patented structure and metal alloy substrate, giving it 40% external quantum efficiency at 350mA. These C3535U-UNx1 UV-A LEDs are capable of operating at high currents (up to 800mA) with high output power density; giving the curing industry a better and more cost-effective solution.We offer this UV reflowed on your choice of two different metal core printed circuit boards (MCPCB) versions: a single (1-Up: 1 LED) and triple (3-Up: 3 LEDs). The 1- Up is a single UV LED reflow soldered to a 20mm hexagonal (LED Star) MCPCB. The MCPCB has four large solder pads for easy solder connections. The 3-Up is three (3) UV LEDs reflow soldered in-series to a 20mm hexagonal MCPCB. The 3-Up MCPCB has two solder pads for connections, mounting holes for secondary carclo optics and a center hole for wires or securing the LED star to a heat sink.