When placed over an SMD LED it will spread the light out. In the case of mini badges help with light up the badge. Using white PLA will work with any color LED use any plastic safe glue to permanently attach.  The diffuser in testing will slip over the led and stay in place if you don't jar it or have too much solder this allows you time to glue it, without clamps. It may work on smaller LEDS this is un-tested.  You can see in the pictures the diffuser with a green led (grim reaper upside down). The grim reaper shows with and without (thanks to Shiffy for the badge) the small bag lets you see the pentagon shape. Printed on elegoo neptune 3Pro.