INTERNAL SAMPLES ONLY / P24-66 / 9231-05 / INTEL 1989
This CPU is one of the first Engineering Sample of the 486 DX2 66. Codenamed P24, the clock-doubled 486 was launched on March 21th, 1992 with the DX2-50. The well-known DX2-66 was launched in late August '92. This particular sample is marked "Internal Samples Only", a very strange marking which mean this CPU wasn't expected to go outside the Intel labs. It was produced in late July '92 with "P24-66" written on top.