The flying shuttle employs a track (the "race") which runs along the front of the beater, from side to side. The shuttle travels in this track. The lower threads of the shed rest on the track and the shuttle slides over them. This allows for weaving on a wide loom without having to physically move from one side to the other in order to "throw" the shuttle.
For the Louet Octado, Spring II and David III Floor Looms.
Louet Flying Shuttle and Pirns
The Looms sold separately here.