The lower hole is made with a small diameter because it does not require a plug. It has both high and low thread mechanisms to secure it to the original material. No plug is required, so the hole diameter is complete with small diameters. It is both high and low screw threads to ensure a secure bond to the other material. For concrete, blocks, and woods. Saddle fastening for wiring and plumbing / display board. Installation, interior substrate Mounting materials and lighting fixtures, etc. Nominal diameter d4 mm / Pre hole diameter (in.): 0.1 inch (3.4 mm) / Embedded depth (in): 0.9 inch (22 mm) / Tensile maximum load (kN): 0.07 inch (35 mm) / Length (1.0 inch (25 mm) / Compatible screwdriver: Plus No. 2 steel / Surface treatment: SV (silver big)
The maximum tensile load is the value of concrete strength Fc21N/m/m²