Machloket the Rambam and rabbeinu Tam. You should try to use a kosher marker Last Updated: 6 years ago in Tzitzit/Tefilin Tags: kosher, marker, Tefilin Related Articles Hi my minhag is not to wear tefilin during minha of a fast- do I need to if im praying with rov wearing tefilin? Rabbi is this teffilin kosher Does one make another bracha if he changed his tzitzis in middle of the day i.e. Erev shabbos? Do sefaradim Put on tefilin on chol hamoed? Of one is unsure of the material of his tallit is it better to attach wool or cotton tzitzit strings? Should I be wearing teckelet How many blue strings should I use and how should it be tied?