What is required to write on the back of an inspection sticker?

To ensure the longevity and visibility of the writing on an inspection sticker, permanent ink is required. This type of ink is designed to resist fading and smudging, which is crucial for documentation purposes as the sticker must remain legible for the duration of its use. Permanent ink provides a clear and enduring mark, allowing for accurate record-keeping and compliance with regulations. Its properties make it suitable for applications where durability is essential, such as on inspection stickers that may be exposed to varying environmental conditions, including moisture and sunlight.

In contrast, pencil marks can easily be erased or smudged, while ballpoint pen ink may not have the longevity required in this setting—potentially leading to illegibility over time. Highlighter ink can also fade or smear, making it unsuitable for important documentation that needs to remain clear and effective. Therefore, using permanent ink ensures that essential information remains intact throughout the sticker's validity period.