These are what we called Russian hooks, but the ones we used were plain polished steel, brass, or copper with a small red dab of paint where the hook joined the body of the jig. Tipped with a maggot they are still our go to when ice fishing for perch. They also come in a different style with a shorter body. Last time I bought them was at the Caslan general store maybe 5 years ago.
https://www.stopperlures.com/best_russian.html