It is very important for you to know the product features, advantages, and benefits before you start your presentation. The feature simply is what it is: “This unit has a USB port.” The advantage is what it does: “This USB port will power and charge your phone, tablet, and other electronics.” The benefit describes how it impacts the user: “This handy feature will help you keep your electronics ready for use at any time and stop those annoying dead-battery delays.”
Again, the feature is simply what it is. The advantage is what it does. To you, the benefit may be so logical that you my feel silly mentioning it. Present it anyway! You are not selling to yourself; you are selling a product to your prospect. Don’t assume what they do or do not know. In fact, presume they know nothing and you will be better off. Think of it this way: your demonstration is no different than singing a song or performing in a play. Every time AC/DC performs “Dirty Deeds Done Dirt Cheap,” they sing every word. They leave out nothing, even though their fans know every word. Performing a demo is no different. Leave out nothing. That one little feature or benefit that you omit may be exactly the one that convinces your prospect to buy.