This is not a stand alone product. You need other Wild Gears sets to use with it. This Gear Set is designed to be a companion set to modular gear sets, the linear pieces are able to expand the modular oblong gear set.
These linear pieces add options for straight lines to modular gear sets. There are two variations of this listing "wavy" and "rack".
The Wavy Linear Modular gear set pieces have a slight undulation to them as they are not fully linear rack gear segments. They go in a net strait line though.
The Rack Linear Modular gear set collects truly strait gear sections. This gear set might be especially interesting as an addition to the Modular Oblong gear set as it will allow for making even bigger oblong rack systems. The Rack Linear Modular gear set comes in large and small sizes.