Christian the ones I've used for the last 27 years are arm indicators, which you can't buy. As they were designed and made by me, predating by 4 years any arm indicators that were commercially available.
Over the years (last update according to my dated drawings was in 1994), I?ve modified them slightly but the basic design still remains the same.
Why arm indicators?
Bobbins have an inherent problem that they swing side-to-side in strong winds (probably the best conditions for bream fishing) and when you fish a long drop 1.5- 2 ft in such conditions they can and do tangle together.
With light bobbins they also have a tendency to creep upwards with the underwater orbital movement.
Swinging is eradicated by arms, and creep can be more or less stopped by a movable counter balance weight on the arm. Yes you can add weight to bobbins, but it doesn?t remove swing and modern, and I use the word advisedly, don?t allow the kind of drop I?ve described with the bog chain they put on them.
Graham I think you need to tell the bream in the current carp water I'm fishing, despite the hundred weights of boillies the carper are putting in, that maggots, caster, worm aren?t viable baits :0)