Type KD / FD Model KD/FD High Filtration Efficiency Type. Type KD・Type FD(magnetic drum diameter: φ216 mm) High Filtration Efficiency Type Features Filtering performance has improved by making the magnetic drum larger. Best model for the fine chip sludge from lapping and honing. Also, for the sludge from the induction hardening that does not attract very well to the magnets. Model KSD/FSD High Filtration Efficiency and Secondary Filtration for Cutting/Shaving Process Type. type FSDmagnetic drum diameter: φ216 mm) Features Large magnetic drum has higher filtering efficiency than Model KS/FS.