For many products, a third-party control is required for the product to be allowed to use for building purposes. Export products are often required to be exposed to a production control procedure. Such products may be prototype-approved, P-marked or certified in another way. The P-mark is SP's own quality mark. It guarantees that the product has been independently controlled and that it meets the requirements of the certification regulations. The marking indicates that the producer must let the product's quality be controlled by SP on a regular basis.