The Televue Bandmate OIII filter passes light from doubly ionized oxygen atoms. As such, it is great for viewing planetary nebulae and supernovae remnants.

The distinction you'll find with Bandmate filters is their consistency, achieved by keeping control of the manufacturing and quality control processes each company does so well. All the materials are sourced in Germany. Each filter is: optically tested by Tele Vue in high power-space to ensure no image degradation, tested by Astronomik on a spectrograph to ensure the coating meets design specifications, mechanically tested for fit, cosmetically inspected for pinholes, digs, and sleeks and serialized, all to insure customer satisfaction. All filters are backed with a 10-year warranty against manufacturing defects.