Protect From Rain

It wasn’t until I blew this shot up to 100% (just to see what it was like) that I noticed on the regulator it says “protect from rain”.   Perhaps I should have read the instructions??
 
The regulator that I got from Calor a couple of years ago was gradually loosing its output pressure (cheap and nasty cheerful – the tails never fitted to the bottles very well and leaked unless you gave the nuts some welly) so I finally decided to buy a good one.  It should have turned up yesterday, but UPS had other ideas and it arrived in the middle of my afternoon nap today.
 
No time like the present to fit it – I think I’ve almost woken up now!
 
Now to wonder if I should really protect it from rain – if I do it will be the first I have seen in some fifty five or sixty years.