2000NF L22-439:2000 Aircraft bolts and nuts - Nuts, hexagonal, plain, reduced height, normal across flats, with locking holes, ISO M or ISO MJ threads, 4H tolerance class.
1987NF L22-439:1987 HEXAGONAL NUTS. REDUCED HEIGHT. NORMAL ACROSS FLATS,WITH LOCKING HOLES. ISO RH THREAD. 4H CLASS.