The Dongcheng DCA DZZ‑90 Diamond Drill with Water Source (Blue) is a handheld, corded core drilling machine tailored for precise wet drilling up to 90 mm diameter (plastic sleeve diameter ~100 mm) in materials like reinforced concrete, stone, brick, and ceramic tile. Its standout feature is an integrated water feed system (including water hose and connector) designed for direct cooling of the diamond bit, minimizing dust and extending bit life—critical for clean, crack‑free operation on hard substrates. Under the blue-painted, double‑insulated housing lies a powerful 1,350 W motor paired with no‑load speeds up to 2,300 RPM (adjustable via built‑in speed control), delivering stable torque and user control across drilling depths. Despite its robust performance, the drill weighs just ≈ 4.4 kg, making it easily portable and suitable for job‑site tasks ranging from HVAC duct, plumbing, and gas pipe installations to municipal sampling and bridge/rail infrastructure work. It ships with a comprehensive accessory kit—including water hose, connector, open‑end wrench, auxiliary handle, shoulder support bracket, carbon brushes, and a sturdy plastic carrying case—enabling immediate deployment and secure handling in extended use. In summary, the Dongcheng DZZ‑90’s blend of compact size (blue), all-in‑one water feed capability, powerful 1,350 W drive, 0–2,300 RPM variable speed, and wide 90 mm drilling capacity, backed by full accessories, makes it a practical core drilling solution for professional contractors as well as experienced DIY users.