The Envoy Pro USB 3.0 Enclosure from Other World Computing is an external enclosure that is designed to house the original SSD found in select 13" and 15" MacBook Pro Retina (Mid 2012 to Early 2013) models as well as 21.5" and 27" iMac (Late 2012 to Early 2013) systems. This enclosure connects via an included USB 3.0 cable and lets you transfer the contents on the stock drive to your new drive. The bus-powered unit draws power from the USB port. Furthermore, the aluminum body protects and passively cools the drive.