This BRNO baLens is for use with lenses that use 55mm filters. Superior White Balance System for digital and video cameras. The baLens is a very high quality snap-on lens cap that accepts a neutral or a warm dome to read the color temperature of the light actually illuminating the subject or scene. When using the camera’s custom white balance setting with the baLens snap cap the photographer can quickly and easily tell the camera what the actual color temperature is for the most accurate in-camera color correction. No longer do you have to read a white or gray card placed in the scene to get the most accurate color. No longer will reflective surfaces confuse the white balance – the baLens works by reading the light falling on the subject – not bouncing off the subject.The baLens also functions as a dependable lens cap. It snaps on easily and tightly, so it is already on your lens and ready to be used at any time.