an improved disposable receiver , formed by foldably nesting a shaped cover element into a correspondingly shaped tray element , for securely encasing sharp disposable surgical implements features a combination of reopenable retaining and locking means for retaining the receiver in the closed , nested position . in a preferred embodiment , the disposable receiver may be formed of transparent plastic material into symmetrical tray and cover portions separated by an integrally formed flexible hinge , and a number of integrally formed pressure fit snap locks are arrayed around the periphery of the receiver to provide readily reopenable closure retaining means . additionally , the tray and cover portions are slightly pyramidally shaped to produce a receiver of high rigidity when in the closed , nested position .