WL-TMRW THT Round LEDs - 3 mm. WL-TMRW THT series 3mm through-hole round LEDs with water-clear encapsulation. These LEDs feature very high luminous efficacy and high reliability with a long operating life. They have standard 2.54mm (0.1in) pitch leads which incorporate PCB stand-offs to facilitate easier installation and assembly. These LEDs produce no UV or IR radiation and are suitable for a wide variety of applications where through-hole devices are required.