The other threads in the "tzitzit" (all the threads, where "tekhelet" is not used) are described as "white". This may be interpreted either literally (by Rama) or as meaning the same colour as the main garment (Rambam). Normally, the garment itself is white so that the divergence does not arise. Similarly the threads may be made either of wool or of the same fabric as the garment; again many authorities recommend using a woollen garment so that all views are satisfied.