This is the complete adapter kit for Intel P-4 socket LGA 775 processors, which allows the CPU-300 cooler to mount LGA 775 motherboards. It includes both the LGA 775 Rails, and LGA 775 Spacer (required for some mainboards), to maintain compatibility with the widest range of LGA 775 boards.
The LGA 775 Spacer is designed for motherboards with tall capacitors near the socket that may conflict with the Koolance CPU-300 cooler. If required, this gold-plated, high density copper piece is installed in between the processor and the CPU-300 cooler to provide clearance on these motherboards. (Thermal paste should be applied to both sides of the spacer during installation.) The spacer is approximately 1.73" (44mm) in diameter, and 0.12" (3mm) thick.