Easy to install. Clean the shaver before installing. Please make sure to check your model compatibility. Fit: For Series 5 8000 51S Replacement Foil Head & Blade Compatible with: 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 sideburn trimmer and you will see the replacement part number (for example, 10B, 30B, 32, 51S, etc.) Grid cover: 4.4 x 2.5 x 2 cm Knife head: 3.1 x 1.7 cm Color: 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 to appear slightly different from the actual product. Measurement allowance is +/- 1-3 cm.