The LFX7 simulates four flashing effects used on a layout. Examples include belisha beacons, emergency services, camera flashes, lightning, sparks, arcing etc. The module comes with 1 Blue, 1 Amber, 1 sub mini Cool White and 1 5mm Cool White LED's, but you can connect up to 4 sets of 4 (16 LED's) in to one LFX. For more LEDs see LED7 (Click Here) 3mm Blue LED is 4.6mm high x 2.9mm diameter (3.2mm diameter at base) 3mm Amber LED is 4.8mm high x 3mm diameter (3.4mm diameter at base) Sub Miniature Cool White LED is 3.5mm x 2.5mm x 2mm high (+ lens) - 1.4mm high x 1.8mm diameter integral domed lens 5mm Cool white LED is 8.6mm high x 5mm diameter (5.9mm diameter at base) 25mm long sturdy wires for easy connection Ideal for fitting in homemade models or kits such as Oxford Diecast and Metcalfe Pack contains 1 Blue, 1 Amber, 1 sub mini Cool White and 1 5mm Cool White LED's, LFX Module and Instructions