Havels 18906 Ultra Pro Seam Ripper Replacement Blades 6/Pkg- Use with the Havels Ultra Pro Seam Ripper #18950 Curved blade ends won't poke or tear fabric. Includes 6 blades, which replace easily with the stainless steel screw-lock handle. Faster, easier cutting even on the heaviest threads! Surgically sharp blades glide through heavy stitches. The Professional's Choice!