Mirka Waterproof Mirka Waterproof is recommended for manually wet sanding topcoats, clearcoats and composite materials. The product has a latex impregnated paper as a backing material and an extra durable grit bonding. Flexible resin bond eliminates cracking, even when folded.  Available in 9? x 11?full size sheets, half size 5-1/2? x 9?, and 3-2/3? x 9?Jitterbug sheets. Finessing discs are ideal for nib sanding to remove dirt and imperfections from clearcoats.