These hair replacement blades are made of metal material, which are corrosion-resistant and wear-resistant, suitable for long time use and can stay pointed, solid and reliable for long time use. Each piece of hair clipper spare blade is designed with 2 holes , which makes it prudent and convenient to operate, ensures cleaner and more stable hair cutting, also be applied smoothly to gilds by most hair types with ease Our adjustable hair clip blades are compatible with 8148, 1919, 8591, 8504, 2241 and 2240, you can simply replace the blades according to your needs and don't need to choose a new clipper, when installed correctly it can work as effectively as a new one Set the adjustable blade lever to the full forward position, place the blade with the small bows on top over the drive finger razor, then place the big lower blade on with the little bows on top of the blade, use the screws and partially tighten, make sure the extreme left tooth of the upper blade is aligned with the first small tooth of the lower blade, then you can tighten the screws, you can turn on and off a few times to make sure your blades are aligned; Note: Screws are not included Color: Black Material: Metal Package Contents: 1 * Large Knife 1 * Small Knife Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement error is +/- 1-3cm.