This double sided pen trimmer head works great for ear, nose, and eyebrow trimming. Get the eyebrow length that is perfect for you with the added 4-position eyebrow guide. You can achieve lengths between 2mm-5mm. This trimming head fits the following Wahl trimmer models: 9937 / 9899 / 9898 / 9888 / 9886 / 9885 / 9884 / 9876 / 9870 / 9867 / 9864 / 9860 / 9854 / 9818.