These are the iTopo map for use on VMS 3DX ONLY unit and is free to download as it is included with the purchase.
1. Download the maps and extract using unrar or winzip software (all the zones, this is only zone 51 and z52)
2. Transfer them to your SD card under a new folder named "raster"
3. Insert the SD card in VMS 3DX unit
4. Go to 3D maps and press the menu button on bottom left side of the screen
5. Go to Raster maps and all your iTopo maps will be showing there