Layered Abrasive Contact Surface: Constructed with dual-layer integrated solid structure combining outer grinding layer and inner buffer layer to form uniform contact plane during surface smoothing work, the matched layered structure delivers steady contact pressure for daily hand-held surface finishing operations across multiple indoor processing scenarios Wide Clamping Compatible Outline: Features flat rectangular outer outline with even smooth backing plane that matches standard hand holding ranges and auxiliary tool clamping positions, the unified outer shape fits regular manual grips and common fixed tool holders without extra trimming before surface treatment work Washable Solid Outer Layer Layout: Equipped with dense compact outer grinding layer attached firmly to inner buffer base through integrated bonding structure, the solid surface layer can be flushed with flowing water to clear surface residual particles after finishing tasks for repeated manual surface processing use Embedded Surface Marking Structure: Built with recessed printed marking area on the rear flat plane of each block, the uniform surface imprint stays distinguishable after repeated contact and simple water flushing to help users quickly locate suitable blocks during continuous surface finishing procedures Flexible Shapable Buffer Base: Comes with compressible inner buffer base that bends gently to fit uneven curved and irregular workpiece outlines, the pliable core structure keeps consistent contact with raised and recessed surface areas durin