This is the new TC-4 Revision 2 with a pure copper base and polycarbonate top. Utilizing additional Ribs in the channels with Copper Turbulators to greatly increase water to copper surface area, water velocity and turbulance which makes the pumps flow more efficient. The 3/8" thick polycarbonate Top is extremely strong and lightweight. It is also much stronger than most acrylic based plastics. The block is made by very tight tolerances with high attention to fit, finish and a perfect O-ring design seal. Price includes AMD Socket A mounting kit and thermal paste. P-4 applications include the adapter kit and mounting hardware and thermal paste. Please be sure to select which processor type in the options dropdown.Comes pressure tested, lapped and equipped with Customs O-ring seated Chrome hose barbs in 1/2" or 3/8".The included all metal mounting kit resists stretching with 4-bolts, 4-nuts, 4-springs, 12-nylon washers, and 4-brass knurled nuts for easy tightening and adjustment.