This is weaving bobbin where you can store yarn and add weights from washer. The inner diameter of the washer must be bigger than 16mm or around 5/8 inch.

For the washer, I use flat washers 5/8 inch. It weighs about 1oz for each washer. The bobbin can hold up to 8 washer. For the hooks, use 5/8inch cup hooks.

You can use it for weaving with a loom for broken threads, floating selvages, tablet weaving with weight system, or for marudai weaving.