When setting a standard rivet the mandrel is pulled which causes the head to deform and form a bulb behind the assembled pieces.
A multigrip rivet forms a double bulb when the mandrel is snapped. The mandrel head remains at the bottom of the rivet enabling a larger clamping capacity. It is suitable for softer materials and is also termed as anti-vibration and weather proof.
When installed with a hammer the mandrel passes through the body of the rivet which splits into 4 pieces. Various combinations of material can be set (wood, plastic, concrete, metal etc.) into a through hole or blind hole.