Linear ball bearings are constituted by a body made of anodized aluminium alloy ,(which presents the characteristics of isolation and strength ) , inside two bushes  ( PTC...SL or PTC...RK) formed by a steel strip appropriately processed and protected by a copper plating or tinning of some microns.  On this tape it is sintered to a porous bronze layer on which is fixed the PTFE (plastic material with extremely low friction coefficient ).

Recirculating ball sleeves  are divided into three series  :

• BA : heavy closed series ( dimensionally interchangeable with the series KB )
• BAO : heavy open series ( dimensionally interchangeable with the series KB_O)
• BAL : light closed series( dimensionally interchangeable with the series KH )

Linear ball bearings of the heavy series BA and BAO that those of the light series BAL are produced in series with two wiper rings which constantly ensure a good cleaning shaft , ensuring a longer life of the internal bushing .

If you want sleeves without sealing rings is necessary to omit the suffix " UU " .

The advantages of these sleeves derive from the fact that the shaft is not tempered ,then the application presents lower production costs , also unlike the recirculating ball sleeves these also allow the rotations on the axis.