Crystic D8151 is a non- accelerated , very flexible polyester resin. It is not usually used on its own but added to other resins to improve flexibility, impact strength etc.
Its elongation to break is around 100% and you would typically add around 20% of it to other resins to get a measurable improvement in elongation to break .
It contains styrene so should be treated like any other polyester resin in terms of health and safety.
If using as a stand alone resin, Accelerator G must be added at 4%