Features: 1Strong Compatibility: This print head is very suitable for WF7521 WF3531 WF7511 WF7011 7018 printers so as to extend the service life of the printer. 2Fadeless: The replacement printhead is made of premium ABS material which is rust proof and non fading and is enough to be used for a long time. 3Guaranteed Function: The printhead has undergone double 100 percent functional tests that is after the completion of production and before delivery to ensure its stable performance. 4Perfect Fit: This printhead can directly replace the original old or damaged part and can fit the printer well which can improve the overall performance of the machine. 5Easy to Store: This printhead is small in size and light in weight and can be kept at home or in the office for a long time in case of emergency replacement. Specification: Item Type: PrintheadMaterial: ABSWeight: Approx. 46g/1.6ozApplicablel: Fit for WF7521 WF3531 WF7511 WF7011 7018 Package List: 1 xPrinthead Note: 1. The printhead may have some protective liquid to give protection to accessories which is normal.2. Solution to Incompatibility: Reset the printer please follow the steps below to reset the printing device. Turn on the printer (if not already turned on). Continue the operation after the printer is completely stationary. After starting the printer disconnect the power cord on the back of the printer. Unplug the power cord plug from the wall socket. Wait at least 60 seconds. Plug the power cord plug back into the wall socket.3. It is recommended to plug the printer power cord directly into the wall socket. Reconnect the power cord to the back of the printer. Turn on the printer (if it has not been turned on automatically). The printer may need to warm up for some time. The printer indicator may flash and the pen holder may move. Wait for the printer to warm up and stop completely before performing the operation. If the above method cannot solve the compatibility problem you need to replace the original inkcartridge and ink.