The Aurora AU-GUF4011/40 11 Cool White PAR20 Lamp is a rather specific lamp designed for use with SGU10 Lampholders only. Note that they have a longer body than the standard style.
“These bulbs are not readily available, so have to be sourced from somewhere like Edwards.They are not cheap.
They give a good bright white light but take a while to get up to their full brightness.
They are a complex design and can be unreliable, although my first one lasted 4 years before failing.”
“These Aurora light bulbs are *** and expensive and don't last very long.
This is my thoughts on the bulbs not on Edwards who I gave 5*.
Unfortunately, I have to use these Aurora bulbs as this is the lighting put in by the builders.”