Avodas Yad Ptil Tcheilet. Available Thick/Thin. Takhelet describe the blue dyed string on tzitzit as described in the Torah. The method fore creating the dye has been lost for over a millennium until being rediscovered. The Ptil Techeilet Tzitzit are made according to two different ways. The Rambam tzitzit are only half blue threads (the other half are white). The Raivid tzitzit are completely blue. Both are available in thick/thin.