When you have a set of files to email and if you zip them all the zip is too large for your email limit. Zip them into a set of zip files

New-CompressedFileSet

<#
Zips a set of files into a set of zip files with a max size to allow emailing of zip files in size-restricted email environment.

Imagine 20 evenly sized files that need to be zipped and when compressed into a single .zip file, the file is 65MB. With an Exchange 
email size limit of 15MB this cannot be sent by email. Using this function you can set a ZipSize limit of 12MB and then the output 
will be 5 .zip files with a size around 12MB and one of around 5MB.

No source file will be spanned across zip files so the actual balance of zip file sizes will vary.

#>

$TargetFolder = "C:\temp\APP"
$ZipNames = 1..9 | % { "APP$($_.ToString('00')).zip"}
$ZIPID = 0
$ZipSize = 15mb

$ZipTarget = join-path -Path $TargetFolder $ZipNames[$ZIPID]

foreach($File in gci C:\temp\APP ){
    if((Get-ItemProperty -Path $ZipTarget -Name length -ErrorAction SilentlyContinue).Length -lt $ZipSize ){
    Write-Output $($File.Name)
        compress-Archive -Path $File -destinationpath $ZipTarget -Update
    }
    else{
    Write-Output $($File.Name)
        ++ $ZIPID
        $ZipTarget = join-path -Path $TargetFolder $ZipNames[$ZIPID]
        compress-Archive -Path $File -destinationpath $ZipTarget
    }
}