The BSA threaded Grand Cru bottom brackets have oversize sealed bearings. The axles are hollow and made from boron steel. Both cups are aluminum alloy. The bearing are well sealed against dust, mud and moisture, with four wiper seals at the bearings and two full contact grit shields at the cups.
JIS taper and includes axle bolts. Generally, it is the crank model not the frame, that determines spindle length. So check what spindle length the crank manufacturer recommends or measure your old BB. If between sizes, it's usually wise to choose the longer.
Use the Park Tool BBT-22 for installation.