Organizations use a variety of techniques to improve conversion rates. The provision of easy credit or payment terms may encourage purchase. Sales promotions such as the opportunity to receive a premium or enter a competition may provide an incentive to buy now rather than defer purchases for a later date. Advertising messages with a strong "call-to-action" are yet another device used to convert customers. A call-to-action is any device designed to encourage immediate sale. Typically, a call-to-action includes specific wording in an advertisement or selling pitch that employs imperative verbs such as "Buy now!" or "Don't wait!". Other types of calls-to-action might provide consumers with strong reasons for purchasing immediately such an offer that is only available for a limited time (e.g. 'Offer must expire soon'; 'Limited stocks available') or a special deal usually accompanied by a time constraint (e.g. 'Order before midnight to receive a free gift with your order'; 'Two for the price of one for first 50 callers only'). Additionally, service convenience is a saving of effort, in the way that it minimizes the activities that customers may bear to buy goods and services. The key to a powerful call-to-action is to provide consumers with compelling reasons to purchase promptly rather than defer purchase decisions.