Internal expansion anchor (Drop‑in anchor) is a flush‑mount mechanical expansion anchor. It consists of expansion sleeve and tapered plug. Install by hammering the tapered plug inside the sleeve to expand the slotted sleeve outward, tightly gripping the concrete hole wall. It is fully embedded after installation, no protruding parts. Suitable for solid concrete, brick and stone. Used for ceiling, HVAC, equipment fixing, light‑medium load fastening. Available in carbon steel (5.8/8.8 grade) and stainless steel (A2‑70 / A4‑80). Thread size range: M6‑M20.