6c Transport, Horizontal Pair, Imperforate Between (C25b). Mint N.H. pair in a horizontal strip of five with selvage at sides (a complete row from a pane of 50), bright color, usual lightened blue crayon post office rejection mark, Very Fine and rare, only 20 pairs were issued, ex Liberman, with 1990 P.F. certificate, Scott Retail for pair with blue rejection mark