Don't put in text convincing the consumer to buy it, that's marketing's job and they have different ideas about things.
What kind of product is it? The specs depend on the device.
They usually want input voltage, current, watts, size and weight. If you have RoHS, FCC, UL and CE compliance, put that in. Tell them what batteries it takes, what connectors and interfaces it uses, that kind of thing.
Don't forget to include in your website's URL if this is in .pdf format or printed on a dead tree.