The Sharpener For Soft Liners has a special double-blade system. This means it has an integrated second blade for improved sharpening and creating a perfectly rounded liner tip. The razor-sharp, lightly curved blades are securely built in, allowing you to sharpen liners quickly and easily. The transparent case allows you to sharpen with precision and has a container attached, making it suitable for use anywhere. The included cleaning stick allows you to remove sharpening residues from the blade quickly and easily.