Midway between the Astronomik CLS and UHC in terms of bandpass, the Baader UHC-S Filter is best used visually by owners of smaller telescopes (8″ or less) for nebular observation or for general observation in areas of high light pollution.
Owners of larger scopes and imagers will get better results with the Astronomik UHC.
The extremely narrow bandpass of the OIII Visual Filter 10nm, brings a substantial contrast gain even under best observation conditions to faint supernova remnants and planetary nebulae . The Baader OIII filter 10nm will often make the difference as to whether the object can be seen or not!