A latex particle for high-sensitive agglutination assay and a reagent for agglutination assay including the particle are provided. The second headstock has a front chuck and a rear chuck for gripping respective workpieces. Thus, detection accuracy of the magnetic encoder of the rotating magnetic field detection type is improved. An apparatus for carrying out the method is furthermore proposed. Each of the assets includes a lock-out mechanism that impedes use of the asset when the lock-out mechanism is activated. A package on package is manufactured by vertically stacking packages to operate a memory semiconductor chip package and a logic semiconductor chip package in a single system.