ESRI Layer Package
For more information about ESRI Layer Packages please see the ESRI ArcGIS website. ArcGIS Explorer Desktop is a free viewer that allows users to view a various types of GIS data formats including layer packages. It can be downloaded for free from Esri.com The full ArcGIS software can open layer packages as standard. Add these files to ArcGIS or ArcGIS Exlorer Desktop using the add data tool or by dragging and dropping the file into your map.
Spatial data can be made available as an ESRI Layer Package. A layer package file allows the creator of the package to include style information and additional properties that can be read by ESRI GIS software.