Yes they are great pins and good workhorses
The late centrepin angler Keith Speers used to swear by them.
In fact it was Keith who introduced me to them in the first place and I have used one for the last few years and I've had many of my barbel and chub and other river species trotting with one.
I don't actually like line guards as I think they hinder my casting and get in my way, and a lot of other like minded pin users remove their line guards on their centrepins for similar reasons.
As has been already said by tigger; the Sheffield doesn't have a line guard.
The Okuma Aventa Pro is also a great trotting pin without a line guard and a little bit cheaper too if you want to spend a little less.
Keith