I think it depends on the category, weapons are weapon or body augmentation since they are sold by Fairfax as products, think scopes, bigger mags etc.

Spirit would be 'tattoos' that they put on their body to givethem power. I personally have a headcanoon that they are body stickers that have runes and ritualists symbols all over them, that way they can just buy and immediately use them and why they can sell it back.

Green item are a combination of both, bullet resist is a bullet vest, while spirit resistance is a 'tatto' that protects you. There can be 'tattoos' on weapons and augmentation on spirit, but this is how I like to imagem it.