This is a set of 8 micro basket filters which are found in Yamaha part number 68F139101000 fuel injectors. They fit Yamaha outboard motors 2000 and up HPDI LZ, Z 150hp 175hp and 200hp and should also fit VZ models. These are the correct 14mm filter that come in the stock injectors and in the HP pumps. The amount of filters you will need varies on your model and number of injectors. Professional instillation recommended, this system runs at very high fuel pressures any leaks could cause a fire or even an explosion. High Pressure Pump Filters are located in the head of the pumps it is relatively easy to replace them but it is high recommended red lock tight is used on the bolts when reassembling. Be sure to also change your pumps gear oil every 100 hours or so this will insure your pump lives a long life, standard Lower unit/gear lube is what is called for in that application. Baskets Can be removed with a basic screw attached to a vise grip simply screw it in and pull it out, be careful not to damage the seat surface, many times the plastic basket will come out without the brass ring attached simply go in again and remove the seat ring. Install new baskets by simply pressing them in, not much force is required. 150-200 use a single headed pump, 250-300 use a double headed pump. It is crucial especially with todays fuels that these filters be replaced all too often lean conditions are created from this very restriction especially on a twin headed pump.