Please contact us for bulk ordering as these are ready for the clean room.  You can use a pack of 25 for a small sample, or your own crafts.  These are 6 inches in diameter.  For those not familiar with the chip making tool, wafers are mirrored on one side, and a dull rainbow effect on the back.  They are not perfectly round to allow for machinery to manipulate them for the creation of microchips.  A wonderful souvenier to hand out for your visitors to Silicon Valley!