X86-Secret : ES Zone
Pentium II 133 MHz ES  (Week 37, Year 1997)   
INTEL CONFIDENTIAL / 80523PX512 Q318 ES / A73716BCA0-156 A4

Here is one of the very first sample of the Pentium II Deschutes. This A0 stepping was the first stepping ever tapped-out from the fab and comes with a CPUID set at 650, while the first commercial CPUID was 651. This sample is not frequency-rated and can't work at 2.5*66 MHz. It only booted up at 133 MHz. That's why we called it "Pentium II 133". It was built in september 1997. The first 0.25 µm Deschutes Pentium II were launched in 1998.