The Nano-Hone NL-4 Lapping Plate is designed to flatten waterstones from 110μm to 10μm (120grit to 1000grit). See chart here.
The NL-4 is a traditional plated design. However, unlike standard designs, the NL-4 has a raised diamond coated structures.
It is the edges of these raised diamond structures that are doing the heavy work.
The NL-4 has an arrow-rake pattern for heavy material removal. The long straight edges cut very well across stones.
Do not use this lapping plate for sintered ceramics or diamond resin stones.
Read instructions here.
Diamond size 130 microns
9.5 x 2.5 x 0.5 inches
240 x 60 x 20 mm