We need double row PLC bearing number PLC 912-39. Also we send you drawings of bearing.1. material must be 42CrMo4V 2. heat treatment must be to hardness 57 to 60 HRC until depth of 0,1 x cut of roller3. Quality of treatment must be Ra 0,8.It is for dredge KU-300/4 "UNEX-UNIČOV" Czech Republic, 1.050. tones. It is round track of unloading rig.