Synapse Necklace Spacy, 41cm, available in two colors: blue and red. This is a set, but individual items can be sold separately. Please let me know in the comments if you're interested in a single item. Designed for athletes and runners, it uses magnetic force and erg power to improve body balance. I received this from a friend but never used it, so it's in unused condition. It has been opened once, but has not been used. The fourth image shows a necklace I own and use, which is different from the one I am selling. It is posted to give you an idea of how it looks when worn. - Model Name: Synapse Necklace Spacy - Color: Blue - Color: Blue - Color: Red - Size: 41cm Thank you for looking.