The double window assembly offers the user an extra layer of reliability by controlling the factors which cause a lens to fail.

If a lens fails, the cause can in most instances be traced to one or a combination of the following factors: a stress concentration, thermal stress or shock, erosion or corrosion and mechanical damage. The double window design provides extra protection against these causes of failure.

All sizes except NW150-DW and NW200-DW are rated standard for 150PSIG (10.3 Barg) pressure and full vacuum at 300°F(149°C) temperature. NW150-DW and NW200-DW are rated for 125 PSIG (8.6 Barg) pressure at 300°F (149°C) temperature. Higher pressure and temperature ratings are available upon request.