This is a brand new OEM GM front carbon ceramic 2 piece light weight rotor which are sold individually. It fits 2009 to 2013 Chevy Corvette Z06 and ZR1 with the Brembo brakes.
GM OEM part # 84023643.
AC Delco part # 177-1120.
Don't confuse this with some people selling cast steel rotors and using the same part number and selling them for less. They weigh more than 2x what these weigh and do not perform the same.
This rotor weighs 13.5 lbs. A steel rotor of this size would weigh over 30 to 40 pounds.
If purchased from a local GM dealer, they would cost about $1600 to $1800 each.