The Kastaplast Impa is a very understable 11-speed distance driver rated 11/6/-4/1. Turn of -4 against a fade of 1 is about as far toward the understable end as an 11-speed goes: it flips readily, keeps turning, and the finish is a gentle settle rather than a hook. Glide of 6 keeps it aloft while it does that.
It is the first Kastaplast driver on this side of the stability chart — the Älva (11/6/-2/2) was the closest before, and the Impa is two full points flippier than that. For slower arms it is an honest distance disc thrown on hyzer; for faster arms it is a roller and sky-anhyzer tool. It is not a headwind disc and it will not hold a flat line at power — throw it flat hard and it turns over.
How much the Impa turns and fades depends on how hard it is thrown. These three shapes are drawn from the manufacturer’s numbers, not from measured throws.
