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/4-wing-concave-non-coring-drill-bit-precision-alignment-anti-deviating-design-for-marble-quarry-horizontal-drilling-3-8m-hr-in-granite-limestone/