Shed roll (a piece of thick bamboo, part of the weaving loom).
It consists of a thick piece of bamboo that is inserted above the thread tabid that forms the heddle. It is used to keep the upper and lower threads apart. The tabid is used to raise the alternate warp threads.
Bang ne kew nulip pellusun gūngen iyan duk pabanga'.
When you insert-colored-threads pull the shed roll out (so the threads are slack) so they can be opened.