Cheap series LED PSU from ebay.

Sorry for the major intensity stepping. My phone was doing some severe light level adjustment due to the reflection of the overhead lighting.
This is a fairly common cheapo LED PSU on ebay that is designed for running long strings of standard 5mm LEDs for applications like signs.
They use a pretty common capacitive voltage dropper, so their output is directly referenced to the mains voltage and should be treated as being live.