A hybrid mattress is a mattress that combines two or more of the major construction techniques for a mattress. The most common type of hybrid mattress is a true hybrid, which combines coils or springs with memory or other foams to produce a unique set of qualities. There is another type of hybrid mattress, called a foam hybrid. This mattress uses different types of foam, for example poly foam and latex foam, to produce a unique mix of qualities to hopefully produce an excellent mattress. Coil Qualities of Hybrid Mattresses
voluntary trade. A term used to describe the foundation of the present economic system. When products and goods are exchanged for other products or services, the result is a trade. Voluntary trade describes a market where buyers and sellers have the right to sell and buy by their own preference or refuse to if they so choose. Voluntary trade also describes a person's freedom to choose to work for compensation versus being forced into labor.
(August 2008). The invisible balance or balance of trade on services is that part of the balance of trade that refers to services and other products that do not result in the transfer of physical objects. Examples include consulting services, shipping services, tourism, and patent license revenues.