What are the elements of a direct mail offer? How can each be tested?

What will be an ideal response?

The offer strategy has five elements — the product, the offer, the medium, the distribution method, and the creative strategy. Fortunately, all can be tested. The direct-mail marketer also must choose five components of the mailing itself: the outside envelope, sales letter, circular, reply form, and reply envelope. A common direct marketing strategy is to follow up direct mail with an e-mail. The different elements of an offer strategy, such as products, product features, copy platform, mailer type, envelope, prices, or mailing lists, can be tested under real market conditions.