The extension PXL identifies spreadsheets created by the Pocket PC version of the Microsoft Excel spreadsheet. It corresponds to an xls file robbed of some functionalities, but uses a different format.
It contains data in cells organized in columns and rows. In addition, the files may also contain graphics, formulas and macros.
The pocket version of Excel can also save normal xsl files, which is preferable because of the greater compatibility. Excel Pocket PC was part of Microsoft Windows Mobile 2003. The successor is now called Excel Mobile and is included as part of Office Mobile on Windows Mobile 5.0.
Older versions of Microsoft Active Sync can convert the files.