A block extraction preserves the original geometry of the source data. When the data is extracted, source layers are not clipped to match the selected polygon/rectangle. As a result, an area much larger than the selection area will be seen when the data is viewed at the full extent in ArcPad; for example: entire county polygons will be displayed. However, the full set of street data is present only for the area within the selected polygon/rectangle.
An exact extraction takes into account the exact shape of the selection. All layers extracted from the dataset are clipped producing the selected shape. Only the data within the selection area will be seen in ArcPad.