Optosupply 5mm superbright cool white current regulated LED

These are very nice, very bright cool white LEDs from Optosupply which have inbuilt constant current drivers, so you don't need resistors.

Rated output is 12,000mcd at a 30 degree beam angle at a typical current of 18mA. Colour temperature is 6500K or higher.

Use them on their own, or in series with other LEDs to control the current in the whole string.

Part number is OSW5DK5A31A-CR18 and datasheet is here.