The basic case for all the ANT-37500 series decoders is the same. please note the files which are .ZIP and .RAR with the same name contain the same information, they are just been saved with different compression algorithms file name ANT-37500_3D.xxx are related to the 3D CAD model ANT-37500_3D.rar - compressed file ANT-37500_3D.stp - 3D CAD file ANT-37500_3D.stp.mp4 - short video of 3D CAD file ANT-37500_3D.zip - compressed file ANT-37500_Internals.xxx are related to the drawing in the internal board ANT-37500_Internals.dwg - drawing file ANT-37500_Internals.pdf - PDF of drawing ANT-37500_Internals.rar - compressed file ANT-37500_Internals.zip - compressed file