Linear ball bearings and linear housing units from the flange series LMEK have a solid steel outer casing and a plastic cage and an integrated square flange. LMEK are particularly stiff. The linear ball bearings LMEK is also reasonably priced and is only available in closed design in a normal long version and a long version (-L) to choose from. All LMEK's at Smalltec have a two-sided seal (-uu). However LMEK bearings have generally no angle error adjustment!