Advertising materials are acceptable as specimens for services (Classes 35–45) but not for goods (Classes 1–34).
For goods, the specimen must demonstrate that the goods are actually available for purchase in US commerce. An advertisement or promotional image shows only that the mark is being promoted, not that the goods are available to US consumers. For goods, a product photo, packaging, label, or a product webpage with a purchasing mechanism is required.
For services, advertising materials; including website content, brochures, and online ads; are acceptable because they can show the mark being used in the sale or promotion of the services, which is what the specimen standard requires for services.