I recently bought a hex die for my cutting tools and it has been a game changer .Based on my observations this industrial and scientific grade hex die is extremely durable and can handle even the toughest metal cuts. The threading is clean and precise, ensuring a perfect fit every time. The only downside is that it's a bit pricey compared to other dies, but the quality is worth the investment..
Being high carbon steel not HSS I don't think it would stand up well to threading in steel or stainless but used for brass with cutting fluid will , it should last forever. Gently cuts new threads and is great for cleaning or adjusting existing threads.