The green band on the Medium Looped-End Economy Wet Mop with Green Band (369551B) is Carlisle's way of indicating the size of the mop head. Yellow is small, green is medium, red is large and blue is extra large. Therefore, establishments that use different sized mop heads for different tasks will not get them mixed up. The 369551B also has some features that set it apart from other brands. It has looped ends, which increase mop head longevity. The 4-ply cotton yarn provides superior absorption, as well, making this mop head ideal for basic cleaning and scrubbing and mopping up liquids.