Using a customer supplied envelope, an individual can mail a Priority Mail Express letter envelope weighing one ounce up to sixteen ounces for $31.20 plus the extra fee of $12.50 to add Sunday/Holiday Delivery.
muscle cell-an elongated contractile cell that forms the muscles of the body. muscle fiber, muscle fibre. fibre, fiber-any of several elongated, threadlike cells (especially a muscle fiber or a nerve fiber).
Muscle cells form the active contractile tissue of the body known as muscle tissue or muscular tissue. Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs.