These are precision ground v-blocks made in the USA.
They start life as powdered metal parts, and occasionally
as they are ground small pits and porosity show up in the block or clamp.
The maker cannot sell them as first quality so I get them at an incredible
savings. V-blocks of this quality regularly sell for $80.00
The dimensions are 1.25" x 1.25" x 1.625" long.
Made of hardened steel, they are precision ground, square to within .0002" over 1", and parallel to within .0002 over 1". They are supplied as matched pairs, with 2 clamps.
This is the typical pitting in a v-block. The pits should cause no inaccuracy and are barely noticeable. The v-blocks are guaranteed, and returnable for any reason.