Insulator-tipped probes are used to test the presence or absence of a component on a printed circuit board. An insulating sleeve around the probe keeps the probe electrically isolated from a flat contact surface, but allows the probe to make electrical contact with a lead or post.
The insulating sleeve is made of Acetal, a durable white plastic that tolerates abrasion well without flaking. The sleeve limits the maximum continuous operating temperature of the probe to 82°C in air. The sleeve is press-fit over a sharp barb, holding it securely.