For Hard To Reach Places. The Sonus SFX-4 Final Gloss Seal and Protect Spot Pad with the Sonus SFX-4 Paint Sealant is the final step to a flawless finish using the Four Step Sonus SFX Polishing System. The 4' size is great for those tight areas the 6' pad simply can't reach! The Sonus SFX-4 Final Gloss Seal and Protect pad is a 4'' Velcro back foam pad that offers safe, thin and even application of your car wax, sealant or protectant. For use with a 3.5' velcro backing plate.Size: 4'