MA275/50 Neutral Density filter Post date October 29, 2015 METTECH » Products Page » Categories » Microscopes » Metallurgical » Upright » MA275/50 Neutral Density filter ND50, 20mm Neutral Density filter in 30mm metal mount. (included) Price: $0.00 Updating cart... ← MA275/30 Green Clear Filter → MA686/05 Adapter