I have the 50 and the 60, both are nice!
The 50 has UVA and UVC activity. A red N$50 appears on the reverse under UVC.

The 60 has a really unusual opaque panel with a black background and gold iridescent overlay. Look at the black portion on the right where the small 60 is. That is a dark charcoal coloured panel.
(Scanned with a white background)

But when tilted it goes bright gold iridescent:

I'll add catalogue images in the next few days.