A feature is what your product or service is. A benefit is what your product or service does for your customers. For example, an anti-virus software program may include weekly online updates. That's a feature. That's the result a buyer wants.
People never buy something to get a feature.
They always buy to get the benefit produced by the feature. Including all 3 methods of promoting a benefit in a small ad can be challenging because of the limited space available. Here's an example of how one business did it with only 18 words. Find out how - before your competition does. Customers buy your product or service to gain the benefit it offers.