Getting extensionAttribute1 using Get-ADComputer

All,

I am trying to check extensionAttribute1 value for computer accounts in an OU. I am running the following command

$Computer = Get-ADComputer Filter * -Searchbase <OU path> -Properties *

It runs perfectly and I believe all the information is stored in $Computer. But the extensionAttribute1 is not visible under $Computer (using PowerGUI). However there is a property of $Computer named PropertyNames and I can see extensionAttribute1 under there. 

Can someone please tell me how I can get this value? I would like to do something like this in the bigger picture

1. Get all properties of all the computers (done using Get-ADComputer) and store it in $Computer

2. For each computer under $Computer, get the value of extensionAttribute1

3. If extensionAttribute is X, do something. If it is not X, do something else.

Thanks.