Zhumell 2" High Performance O-lll Telescope Filter

This particular filter allows light transmission in the doubly ionized oxygen wavelengths.  This is particularly good for viewing double star systems where a lot of emissions are in the doubly ionized oxygen range. 

Oxygen III (O-III) are great for viewing diffuse and planetary nebulae.  The views of the Veil, Ring, Dumbbell, Crescent and Orion nebulae are dramatically improved.