With GET  EDIT,  reads  a  'w'-character  string  composed  of  the
  characters 0 and 1; with PUT EDIT, converts the corresponding value
  to a character string.

  B1 [ (w) ]

  w:

  A nonnegative integer or an expression capable of  being  converted
  to  an  integer that specifies the width in characters of the field
  in the stream.