The filter is a multi-band pass filter which transmits a high percentage of light in the visual spectrum. It will enhance contrast when observing brighter objects such as the moon and planets and in the same time will suppress sky glow from artificial lighting and background reflected glow. The filter has a mild effect of darkening the background of the night sky so that the fainter objects will be against the dark background, excellent for observing planets. The filter will fit all standard sized 1.25" eyepieces and accessories such as Barlow lens etc. It is mounted in a nicely anodized Al alloy housing and is threaded on both sides for stacking with other 1.25" filters if necessary. The following filters are included in this kit: #23A Light Red- The red filters are made from renowned Schott and Hoya optical glass and allow for maximum contrast on viewing planetary and lunar detail; #12 Yellow - The yellow filter improves contrast on Moon craters, on Mars, channels and polar caps become more apparent; #80A blue - The light blue filter is suitable for Moon, Mars, Jupiter and Saturne observation. It improves contrast on faint areas without affecting the planet's brightness; which is why this filter is often used in combination with others; #56 Light green - The light green filter is ideal for observing the ice caps on Mars and the yellowish sand storms on the Martian surface. It also improves the contrast of reddish and bluish structures in Jupiter's atmosphere; #47 Violet - The violet filter totally blocks red, yellow and green light, which is useful when observing the polar regions on Mars, with larger telescopes". It also allows to distinguish some structures in Venus' atmosphere; Variable Grey Polarizing Filter - The variable polarizing filter allows for selective adjustment of brightness, which is useful for terrestrial observation. Light transmission of polarizing filters is between 1% and 40%.