Good to know- Sharpen up your Philips S3000 or square S1000 shaver with these replacement heads- These self-sharpening steel precision blades can last you up to 2 years- With 90,00 cutting actions a minute, these blades mean business- You can easily replace the shaver head in just a few stepsPlease note: These replacement heads are compatible with Philips Series 1000 & 3000 shavers.