Shrink:

Shrinking is always applicable to pre-packed products. This technique has two options:

• show pack: the product is completely overhauled with shrink film. This option is often used for promotional packaging, e.g. to ensure that a giveaway is nicely displayed.
• bundle pack: often used as a wholesale packaging, to pack several individual packs as one pack. 

Overwrapping:

Overwrapping upgrades the presentation of the product, but can also improve its shelf-life. Overwrapping can also be used as a bundle pack to create a larger sales unit. An overwrapping machine takes a length of heat sealable film and folds it around a product. The folded film is closed by means of heat seal.