... and industrial equipment, etc4. Precision Level: P0, P6, P6x, P5, SP, P4, UP (ABEC1, ABEC3, ABEC5);5. Noise Level: Z1, Z2 ... blower,air compressor,various types of transmission,fuel injection pumps,printing machinery.Structure available:S,B,C,AC,C/DB,AC/DB ...