Latest Deals!

Open Box ZWO 31mm OIII 7nm Filter

  • Sale
  • Regular price $149.00
  • $109.00
  • You save: $40.00 (26%)

Add to Wishlist
Already have gear? Trade it in for cash or new equipment.

Accessories Added

  • This is an open box filter in like new condition


Open Box ZWO 31mm OIII 7nm Filter

Passes 7nm bandwidth of light centered on a 500nm wavelength, which corresponds to OIII emission lines. All other light is blocked.

Adding a ZWO O-III Narrowband filter to your imaging collection will take you beyond RGB imaging and reveals your favorite nebulas in a totally new light, no matter how polluted your skies may be! 

  • FWHM: 7±0.5nm
  • Glass Thickness 2.0+/-0.03 mm (1.25”/31mm/36mm)
  • Fine-optically polished glass ensures accurate 1/4 wavefront over both surfaces
  • Approx 90% transmission at major OIII line 500nm
  • Infrared wavelength 700-1100nm cut-off
  • <0.1% transmission of off-band, OD3 (Optical Density)


ConditionLike New
Warranty90 Day Covered By OPT


  • ZWO OIII 7nm filter
  • Plastic case, wrapping and outer box