ZWO LRGB Imaging Filters - 2" Mounted - LRGB2

The ZWO LRGB 2" mounted filters offer good color separation, multi-layer anti-reflection coatings, and more than 92% transmission at passband.  

The RGB color combine weights will be approximately 1:1:1

• Fine-optically polished to ensure accurate 1/4 wavefront
• More than 92% transmission at passband
• Infrared wavelength 700-1100nm cut-off
• Precision off-band blocking
• Multi-layers anti-reflection coating
• Small spectral gap to minimize effect of light pollution
• More parfocal; thickness 1.9+/-0.03mm
• Thickness is 5mm + 2.5 mm for the thread
• Thread:  M48*0.75 with a thickness of 1.85mm

Sometimes it's hard to tell which side of the filter is the top, and which is the bottom.  The image below should help you: