Abstract: A jacket for a mobile device, having a retention well with a perimeter wall and a base member, a first perimeter rail surrounding the retention well, a second perimeter rail surrounding the first perimeter rail, a secondary well formed between the first perimeter rail and the second perimeter rail, and a resilient wrapper enveloping the retention well. The resilient wrapper includes a perimeter ridge formed to fit over the second perimeter rail, to fit into the secondary well, and to abut the outer side of the first perimeter rail. A device can have a top cover with a first perimeter rail, a second perimeter rail, and a secondary well, a bottom cover formed to receive the mobile device, and a resilient wrapper including a perimeter ridge to fit over the second perimeter rail, to fit into the secondary well, and to abut the outer side of the first perimeter rail.