This is a Mapp Caster listing and you receive exactly what is pictured - including zerk axle. If you order from other sellers we can not guarantee that you will get what is pictured as we have had knock problems previously. This 6" x 2" sliding interior barn door wheel kit is similar to our popular LVG314-KIT3/8, however this barn door wheel is larger and comes with sealed 1/2" ball bearings, offering a quiet and smooth ride along the track. These wheels are bigger than the average barn door wheels and are meant for larger barn doors or for a oversize wheel look. Make sure you have enough space from where the track will be hung to the ceiling to accomidate this wheel. You will need 5-7/8" of space for the wheel, not including any brackets. The wheel has a a .24" opening in the v groove and can be run on 3/16" flat bar, or various size round bar or angle