I've got a couple of those. ANSI yellow/yellow reflective material, red flashing LEDs and black/silver reflective material, red flashing LEDs. They work very well. The LEDs are for visibility when there's no secondary light source to be reflected. As such, they are a whole lot more visible, and from much further away, than a vest that relies on reflective material alone.

The black/silver one matches my road bike. How the mother-in-law knew that when she got these for me, I have no idea. What it was, was the place she got them from had both colors, so she bought both. If they had, had a third color combo, she'd have bought that too.