{HEAD ~ The rolling elements} may comprise ball bearings, spherical elements, {TAIL ~ cylindrical bearings}, tapered roller bearings, or any other suitable friction reducing element 
comprise
{ HEAD ~ The rolling elements } may comprise ball bearings , spherical elements , { TAIL ~ cylindrical bearings } , tapered roller bearings , or any other suitable friction reducing element
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH