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.
(ECN) is a document authorizing and recording design changes. throughout the prototyping and life-cycle phases of a product. ECN documentation contains the. justification for changes made to a component or system once the initial design is complete. It also. forces changes to be approved by the relevant authorities (often the project manager).