Class L (light) : For any portable corded or cordless drill, with or without percussion WARNING : A single sleeve keyless chuck is suitable for cordless or corded drills with spindle lock only. # Capacity : 10 mm, 13 mm (with or without locking system) # plastic sleeves # Available threaded mountings : 3/8 - 24, 1/2 - 20 # Available tapered mountings : J2, B12, B16 # With or without any through hole. Class M (medium) : For any professional corded portable drill, with or without percussion. # Capacity : 13 mm (with locking system) # metal sleeves # Available threaded mountings : 3/8 - 24, 1/2 - 20 # Available tapered mountings : B12, B16 # With or without any through hole.