Poseidon 3-Strand Waist Belt (150cm) Black Silica (Graphite Silicon)

This item was purchased by my mother over a decade ago when she was suffering from back pain. She bought two sets, one for herself and one for me, and gifted me this one.
Length: 150 cm

I used the set I received about 5 times, and then stored it in its case.

It seems my mother purchased each set for approximately 100,000 yen at a local independent jewelry store.

This is more of a belt-type item to be worn around the waist rather than a necklace.

My mother's set was also used, so I will include it as a bonus.
There was also one part of the clasp on the gifted item that seemed unusual. I believe this was a manufacturing defect.
I would like to list this as 1.5 sets, taking into account the market price at the time.
Thank you for your consideration.