Spacers and standoffs

Shapes include flat sheet, cylindrical and spherical.A standoff is a threaded separator of defined length used to raise one part in an assembly above another.

They are usually round or hex (for wrench tightening), often made of stainless steel, aluminum, brass, or nylon, and come in male-female or female-female forms.

In some cases (e.g., D-subminiature connectors), short standoffs may be used to receive the jackscrews that lock the connection together.

In contrast, some spacers may look similar to standoffs but are unthreaded pieces of tubing which let the entire bolt pass through.

Dell, Inc. refers to standoffs that receive thumbscrews as "hex nut screws" and measures them with the metric system.