Product Line Length
Companies seeking high market share and market growth will generally carry longer product lines. Those emphasizing high profitability will carry shorter lines of carefully chosen items. However, consumers are increasingly weary of dense product lines, overextended brands, and feature-laden products (see “Marketing Insight: When Less Is More”)
A company lengthens its product line in two ways: line stretching and line filling.
Line stretching occurs when a company lengthens its product line beyond its current range. A firm may choose a down-market stretch—introducing a lower-priced line—to attract shoppers who want value-priced goods, battle low-end competitors, or avoid a stagnating middle market. With an up-market stretch, the firm aims to achieve more growth, realize higher margins, or simply position itself as a full-line manufacturer. Companies serving the middle market might stretch their line in both directions.
With line filling, a firm lengthens its product line by adding more items within the present range. The goals are to reach for incremental profits, satisfy dealers who complain about lost sales because of items missing from the line, utilize excess capacity, try to become the leading full-line company, and plug holes to keep out competitors
Example: Line Stretching
Take a look at Samsung Smartphones. Where Samsung has premium smartphones like the Edge series, it also has the A series of cheaper smartphones so that it does not lose the massive consumption which happens in cheap smartphones. Does, Samsung does a lot of down market product line stretching.
English 
Dutch