Plain Encased Seal

A pliable rubber, felt, leather, or composition ring-shaped element, split or solid; with or without spring or spreader, having a metal shell on all or a portion of at least two of the outer surfaces. It may be designed to be either bolt mounted or pressmounted between fixed and moveable parts to form a tight and effective seal by the pressure of the spring or spreader or the resiliency inherent in the element material. Excludes packing with retainer.