This is a pipe swivel for bottom fishing, suitable for fishing for fish like Japanese striped knifejaw (Ishidai) and longtooth grouper (Kue). It's designed to improve bite detection with a sliding weight and to reduce snagging. The diameter is 4mm, and it easily accommodates up to 100-gauge nylon line. The price has been reduced to the limit, so further price reductions are difficult. I also have other large fish rigs, bottom fishing rigs for rocky shores, and live bait rigs for horse mackerel (Muroaji) available. If you purchase multiple items, I will discount the shipping costs, so please leave a comment.