When we are detailing our scale models or Gundam models, we often have to scribe panels. And we want them to be -say- at 15 mm from the edge of a panel.
With a regular panel scriber, we have to draw the line, and use some kind of guide like an elastic ruler or even masking tape to (hopefully) scribe the panel in the correct place and not deviate and make a mess of the model.
This tool has an adjustable scribing blade and a guiding plate. You adjust the blade at the distance you want from the guide, place that guide against the edge of the model, and start scribing, knowing that the distance will be constant.
And the best thing is, it works on curved surfaces, the hardest ones to scribe correctly with traditional methods.
We have to prepare each shipment individually as they are ordered, so allow it in 3-4 weeks to arrive in the USA/Canada (to be safe) and 3-6 weeks rest of the world, though they are usually delivered much faster.