Stretch fabric pieces, in various colours, black and whites, may be powernet, sports fabric, mesh, knicker fabric, cotton jersey.  Good mix, occasionally a non-stretch bit might sneak in the bags! 

The pieces are around A4 size (21cm x 30cm approx), so not big pieces, but possibly adequate for making thongs, adding contrasts, etc.

These fabrics are NOT available by the metre.  Packs vary greatly.