X86-Secret : ES Zone
P-Pro 133 MHZ 256K ES  (Week 26, Year 1995)   
KB80521EX-133 - 2526242BAA MALAY K - Q0815 256K NOT FOR SALE

The Pentium Pro was very expensive at launch time and only intended to be used on server and high-end workstation. All the P6 line began on November, 1995 with the Pentium Pro. This engineering sample comes with 512 KB of L2 cache and a clock speed of 133 MHz (66.6 * 2 MHz). This clock speed was never released and this sample was produced in mid-1995. The first Pentium Pro 166 was launched on November, 1st.