I accidentally bought the wrong size. I opened the box a little, but it's new and unused! I tore it open, so I've taped the back with paper ( >_< ) If "the blades don't get sharper even after removing lint" or "the blades have become dull," there's a possibility that the blades are deformed, worn, or damaged. We recommend replacing the blades regularly (approximately every 1.5 years). ■ Specifications Compatible models: Panasonic Facial Hair Trimmer ES-WF40 / ES-WF41 Package dimensions: H 10.6 x W 8 x D 0.8 cm