The following description was prepared by William Gross:
Religious Jews put on Tefilin - phylacteries - every weekday morning and they were carried to the synagogue for this purpose. To make this transport easier and to protect the Holy objects, the Tefilin were usually placed in a container, most often fashioned from some sort of textile. Such was the custom in most countries where Jews lived.
This Tefilin bag was retrieved from the Genizah at Westheim, in southern Germany. It was fashioned from a beautiful yellow silk fabric and was embroidered with a 'yud' and a 'resh', standing for Yad - Hand - and Roshe - Head. Most of the Tefilin bags found in Genizas are from simple printed cotton. Such small bags were usually made for the Bar Mitzvah child for his first pair of Tefilin. Inscription: Resh Yud (Rosh Yad)