An apparatus and a method for calibrating the position of a wafer platform in an ion implanter, and particularly in a medium current ion implanter. The brush is in contact with a floor of the container in a second position displaced from a first position to permit the brush to project interiorly of the container for access to fluid on the floor of the container. Spinal implant kits having multiple spinal implant pieces derived from a common source also are disclosed. The film exhibits an excellent property for preventing reflection of light and excellent scratch resistance and can be produced at a low cost. Also, the present invention provides a duplex sheet feeding system having the sheet ejection mechanism.