lk-99 is the lead-copper material used. It was developed in 1999. Think of it like LSD being invented but then 5 years later, someone spills it on their hand a

lk-99 is the lead-copper material used. It was developed in 1999. Think of it like LSD being invented but then 5 years later, someone spills it on their hand and trips out for 2 hours. (True Story)