PowerShell: Search Multiple servers to see if a specific program is installed

Scenario:  You want to quickly search multiple remote servers to see if a specific program is installed.

Script: The following script checks to see if Wireshark is installed on any of our Exchange servers.

#Declare Server Variable
$Ex2013 = Get-exchangeserver ex* | Select -expandproperty Name

#Perform the Query against each server
$Ex2013 | %{"Checking WireShark on $_";Invoke-Command -Computer $_ -ScriptBlock {

#Declare App
$appToMatch = '*Wireshark*'

#Determine Uninstall Directory
if ([IntPtr]::Size -eq 4) {
        $regpath = 'HKLM:SoftwareMicrosoftWindowsCurrentVersionUninstall*'
    } else {
        $regpath = @(
            'HKLM:SoftwareMicrosoftWindowsCurrentVersionUninstall*'
            'HKLM:SoftwareWow6432NodeMicrosoftWindowsCurrentVersionUninstall*'
        )
    }

#Get all Programs Installed
$1 = Get-ItemProperty $regpath | .{process{if($_.DisplayName -and $_.UninstallString) { $_ } }} | Select DisplayName, Publisher, InstallDate, DisplayVersion, UninstallString |Sort DisplayName

#Filter based on program
$result = $1 | where {$_.DisplayName -like $appToMatch}

#Display the result if found
If($result -ne $null){
    Write-Host "
    The following matching $appToMatch are Installed on $($env:computername) " -ForegroundColor Yellow
    Write-Host "$($result.displayName)
    " -ForegroundColor Yellow
}
 }}