Bonsai Drainage Mesh or Bonsai Pot Mesh is used to keep your bonsai soils from falling through the drainage holes in your bonsai pot. Pieces can be cut to size and fixed in using Bonsai wire. 1 packet of Premium Japanese Made Bonsai Pot Mesh. Black Colour. Mesh size 3mm. Packet contains 5 x sheets 140mm x 200mm.