A one-piece thermoformed packaging cap for article shock-protection which has two elongate wings integrally hinged and have upstanding shoulders which define a channel that receives part of the article. Ridges and grooves run along the shoulders of each wing such that when the wings are folded abut each other, the ridges and grooves of one wing nest within those of the other wing and provide cushioning and lateral interlocking between the wings. Caps can have four wings and wrap the entire perimeter of the article and may incorporate a locking tab to secure the wrap. Alternatively, an assembly of partial wrap-components can be locked via flap-tabs. For locking, a projection of one wing enters into a recess of another wing, and a locking flap of the latter wing is folded and a projection of the flap is snapped into the reverse recess of the thermoformed projection.