of the roller rack to minimize the possibilities of materials catching therebetween and fouling the roller 710 in this embodiment it has been found that sufficient bearing area is provided and the removal of the central part of the bearing does not adversely affect the longevity of the roller 710 in still another embodiment depicted in fig8 the end of the roller 810 may be bored to accept a bearing 834 the bearing 834 may be any of the numerous types of readily available bearings such as a ball bearing roller bearing needle bearing or the like bearings 834 of this type are well known in the art and readily available from numerous sources although it is not required the bearing 834 may be a sealed bearing the bearing 834 is set into the end of the roller 810 leaving the bearing extending slightly out from the end of the roller 810 so that the bearing may perform the same function as the shoulder 716 of the roller 710 shown in fig7 the material making up the housing of the roller should have a compressibility strength sufficient to allow the roller and aperture to remain generally round as cargo passes over the conveyor should the roller or aperture become overly distorted the rollers will not rotate and will impede the movement of product or cargo along the conveyor it has been found that a compressibility strength of 20 psi or greater is suitable for aircraft conveyor systems desirably a roller of the invention may have a compressibility strength of at least 20 50 100 200 500 1000 2000 psi or greater when the roller is used in aircraft conveyors the compressibility strength causes the roller to either lose or retain shape as weight bears on.