A blister pack is a type of product packaging where merchandise is shipped with a descriptive card under clear plastic wrap. In addition, a blister pack can be packaged in clear or opaque plastic or metal-foil seal which holds the product against a sheet of cardboard.  Blister packs are useful for protecting the product against external factors such as humidity and contamination for extended periods of time. Opaque blisters also protect sensitive products against daylight. Another term for blister pack is bubble wrap.