Crystals 340W18GN00, crystal, Seiko helmet 6139-7100 / -7109 NextSeiko 330W18GN00 'Cevert' crystal 6139-6000 / 6001 / 6002 / 6005 Proof & Resist models 340W18GN00, crystal, Seiko helmet 6139-7100 / -7109 340W18GN00, crystal, Seiko helmet 6139-7100 / -7109 $60.00 Replacement Hardlex crystal for all models of the 6139 helmet chronograph. Quantity: Add To Cart Facebook0 Twitter LinkedIn0 Reddit Tumblr Pinterest0