These lights have 'Wide' or 'Narrow/long' mode. The lens needs to be rotated 180 degrees to make the switch.
They ship with 'Wide' as the default. I installed one wth default, Wide, a couple weeks ago.
I like the light but am considering changing to 'Narrow' to bring some extra light to the shallow end.
However it's kind of a pain... I'll have to order a new gasket, remove light, go through the fiddly process, etc.
Have you made the change from wide to narrow (or the other way round)? What was your experience? Worth it?