The clean pass ramps of CLM differ from the standard product due to the fact that the surface on which the tyre/track runs is supplied with a special riddled surface that is spaced to create slots across the whole surface of the ramp.
CLM has devised the clean pass ramps to prevent the riddled surface on which the tyre runs from getting clogged up with mud, stones, water and so on.
The slotting system stops the ramp surface from getting clogged-up, consequently there is no risk of the tyre/track slipping on it and it also actually cleans the wheels/tracks while the vehicle climbs the ramp, so that as little mud, rubble etcas possible is taken onto the truck bed.