Easy to install. Clean the before installing. Please make sure well your model. fit:For Series 5 8000 51S Replacement Foil Head & Blade Compatible with:For all 51S models including: Type: 5643, 5644, 5645, 5646, 5647, 5649, 5751, 5757, 5758 Model NO: 8970, 8975, 8985, 8986, 8987, 8990, 8991, 8995,8595, 8795, 8581, 8583, 8585, 8588, 8590, 8781, 8783, 8790, WF1s, 510, 550, 560, 570cc, 590cc,530s-4, 550, 550s-3, 550s-4, 550cc-4, 560, 560s-3, 560s-4, 565cc-4,570cc, 570cc-3, 570cc-4,590cc, 590cc-3, 590cc-4, 8385 C&R,8374, 8377 - Series 5, ContourPro Note: The method of checking the replacement part number of the shaver is as follows: Push open the for shaver's sideburns trimmer and you see the replacement part number (for example, 10B, 30B, 32, 51S, etc.) Grid cover: 4.4x2.5x2cm Knife head: 3.1x1.7cm Colour:Silver Material:Nylon+stainless steel Package Contents: 1 x mesh cover 1 x knife head Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.