Needlepoint canvas 

There are two types of canvas for tapestry: mono and Penelope. Mono canvas is woven in squares and is generally the type that it is used for classic needlepoint on the diagonal. Penelope canvas is woven with double threads and is finer. The double weave makes it perfect for techniques requiring more detail. This can be seen on vintage tapestries in the finesse of hands and faces, often sewn using different threads than the rest of the surface.