The plugs work because the tip is pulled towards the top of the plug causing it to expand in the door panel. The plug length is 24mm. The screw must be long enough to grip the tip of the plug after passing through the item that is being fixed to the door. A 30mm 3.5mm screw would be good for most hooks but extra length might be needed. 25mm long screws do not work, they are not long enough to grip the tip of the plug properly. Don't use 4mm wide screws as there is then a risk of snapping the plug into 2 bits. Plasplugs could do themselves a favour by explaining this on their packaging.
Answered by: IanRB2
Date published: 2021-09-06