1.There is screw hole in the bottom, fixing with self-tap Screw. 2.To fix the PCB without tools, easy to install and unload anti-erode, good insulation with long life. 3.Ideally suited for PCB packaging and stacking applications, these new spacers/supports come in seven popular styles. 4.Spacers/supports are available in a wide range of spacing heights and will meet almost any PCB packaging need.