3M Company 99421NA 320 Grit Sandpaper 9x11 Inches 25 Pack

Product Description

The 3M COMPANY 99421NA is a silicon carbide wet or dry sandpaper sheet designed for fine finish sanding on paint, varnish, and similar coatings. Each sheet measures 9 inches by 11 inches and carries a 320 grit rating, making it well suited for smoothing between finish coats or preparing surfaces for final application. The flexible A-weight paper backing conforms to contoured surfaces, allowing consistent abrasive contact on curved or irregular workpieces. Sheets can be used wet or dry depending on the task. This product is packaged 25 sheets per box and is a staple consumable for finishing work in woodworking, auto body, and general surface prep trades.

The 99421NA is used across residential and commercial finishing applications where a controlled, fine abrasive cut is needed. Typical scenarios include scuff sanding between paint or varnish coats on furniture, cabinetry, trim, and automotive surfaces. The wet or dry capability makes it suitable for both waterborne and solvent-based finishing systems. The flexible A-weight backing allows the sheet to be hand-wrapped around sanding blocks or used freehand on contoured profiles without cracking or tearing prematurely.

Key Features

• 320 grit silicon carbide abrasive for fine finish and between-coat sanding
• Wet or dry use compatible with waterborne and solvent-based finishes
• Flexible A-weight backing conforms to contoured and irregular surfaces
• Full 9 inches by 11 inches sheet size for standard hand sanding and blocking
• 25 sheets per box with tri-lingual die-cut packaging

Compatibility

Designed as a general-purpose finishing abrasive sheet for use on paint, varnish, and similar coatings in woodworking, cabinetry, automotive, and general surface preparation applications.

Installation Notes

No power tools or trade licensing are required for hand sanding applications. When sanding wet, ensure the workpiece and work area are appropriate for water or solvent use, and allow adequate ventilation when working with solvent-based coatings. Wear appropriate respiratory protection and eye protection when dry sanding to limit dust exposure. Inspect sheets before use and replace when abrasive loading or wear reduces cutting efficiency.

Technical Specifications

• Grit: 320
• Abrasive Material: Silicon Carbide
• Sheet Size: 9 inches x 11 inches
• Backing Weight: A-Weight (Flexible)
• Use Type: Wet or Dry
• Sheet Count per Box: 25
• Package Quantity: 10
• Unit of Measure: PK
• Weight: 11.4 pounds

Standard Information

• Brand: 3M COMPANY
• Manufacturer Part Number: 99421NA