Kinze single notched blade fertilizer openers. These will place fertilizer in a 2x2 or 3x3. Used one season @1500 acres. We bought the planter new (3660 with interplant) and had these on it. We decided do use a different placement system after the first year. They come with the mounting brackets ( I believe they would fit on other makes and model of planters) Have 16 of them available. (The photo is off the website I will get some actual photos of them up tomorrow they do not include the guage wheel)