They have hardened short steel pins pre-loaded. They are designed for use where the plaster is very thin, so that most of the pin length goes into the wall material. Wall surfaces vary, so always check before hanging a picture.

Hook Type: Extra Small - 1 Pin
Pack Size: 2
Sub-Type: Picture Hooks
Brand: Lord of the Frames
Type: Hanging Hardware
Size: 12mm - 41mm
Colour: White