Hunan Fengsu‑Drill (fsdrill.com) is a Chinese manufacturer and supplier specializing in high-performance drill bits and related drilling equipment. With 15 years of experience, the company produces a variety of PDC (polycrystalline diamond compact) drill bits—such as multi‑wing, non‑coring, and hot‑press core bits—used in mining, geological exploration, water well drilling, grouting, ... https://fsdrill.com/product/3-wing-concave-spiral-pdc-bit-stable-non-coring-drilling-for-grouting-hydrological-holes-in-backfill-dolomite-3-6m-hr-o94-98-113mm/