This set of thick wool Radzyner Tekhelet Strings includes four dark blue strings that follow the Radzyner Hassidic tradition features dye from the cuttlefish and squid. This set of Tekhelet Strings is thick and is meant to be attached to a Tallit Gadol although they can also be used with a Tallit Katan. This set of blue Tekhelet strings does not include white strings that are used together with Tekhelet. The dye on these Tzitzit can fade over time and will rub off over time. This is normal and does not mark the strings as defective.