These No7 Radiant Results Revitalising Cleansing Brush Heads are replacement heads for use with the No7 Radiant Results Revitalising Sonic Action Cleansing Brush.Instructions for Use: Please read the following instructions carefully before first use and retain for future reference.To fit your new brush heads:1. Remove the used brush head by holding the device and head securely in either hand then pulling them firmly apart2. Ensure the drive shaft of the cleansing brush unit is placed into the hole at the back of the new brush head and then push until you hear a click3. Use the device and new brush head as instructed in the leaflet provided for your No7 Radiant Results Revitalising Sonic Action Cleansing BrushWe recommend that you replace your brush head every 3-4 months to ensure the brushs performance is maintained.