This is a Used Set that came out of a Large Machine Shop's Inspection Room. Appears to Be Complete and in good condition except for the chip in back corner on outside of box. And if you Look at pictures, #4 Appears to be less shiny then the rest, perhaps patina. I would not go as far as call it surface rust.#4,5,& 6 obviously have 2 different finishes on each side as shown.

S.PI Official S.PE Mold Finish Comparison Kit - Inspection Tool. Condition is "Used". S.PI Official S.PE Mold Finish Comparison Kit In 1962, the Moldmaking Divs. of the Society of Plastics Engineers (SPE) and the Society of the Plastics Industry (SPI) cooperated in establishing mold finish standards for the injection molding industry. This standard specified six finishes, ranging from a high diamond polish to a rough, blasted surface. This standard was controlled

by a set of six steel disks containing each of the six finishes. The surface finish standards on molds is often specified by the SPI-SPE Mold Finish Comparison Kit. It consists of six steel disks polished to different levels. The polishing technique employed to obtain the six different mold finishes, and the surface roughness measured in RMS microinches are shown in Table 1. 1 #3 Diamond Polish 0.5 to 1.0 2 #15 Diamond Polish 1.0 to 2.0 3 320 Grit Abrasive Cloth 7.0 to 7.5 4 Stone 12.0 to 15.0 5 240 Grit, Dry Blast (5 inch distance @ 100 psi) 26.0 to 32.0 6 24 Grit, Dry Blast (3 inch distance @ 100 psi) 160.0 to 190.0

INV# I-032