Useful and well made,
This review is from: Faithfull TRAMMEL 31mm Capacity Trammel Head Set Bar (DIY & Tools)
I've long had a cheap plastic set of trammel heads which actually were useful and well designed but I needed "proper" trammel heads with a long point which could also be more firmly clamped on a batten. I initially required them for use with a spirit level on a long batten for accurately placing screw plugs in walls for hanging very large (8' long) whiteboards but I also found them much more widely useful, for example for taking measurements between two points when a rule or tape measure cannot be used easily or with accuracy. Another maker produces a set with micro-adjustment which in theory should enable more precise measurements and markings-out but so far I haven't found that these would be any better for my purposes. Similarly, there are beautifully made brass and steel trammel heads which would be a pleasure to own - but they offer no practical advantage, at many times the price!
I recommend these.