Abstract: A lockbox is disclosed having a base that includes a first engagement structure and a cover that includes a second engagement structure that slidingly engages with the first engagement structure. The lockbox may further include a locking mechanism configured to secure the cover to the base. The base and the cover may define an enclosed volume when the cover is secured to the base and the first and second engagement structures may be located substantially within the enclosed volume. The first and second engagement structures may permit movement of the cover relative to the base in only a single direction when engaged. One of the first and second engagement structures may be at least one groove and the other one of the first and second engagement structures may be at least one rail.

Abstract: A system for simultaneous frequency trimming of a plurality frequency devices such as oscillators, crystals and surface acoustic wave filters and resonators by removing intrinsic or previously deposited material through plasma ion bombardment is comprised of a plasma ion chamber, a magazine rack, a vacuum evacuator, a control console, a plasma power supply and a frequency evaluator. The system employs a shutter assembly and shutter control mechanism to individually regulate plasma ion bombardment of a plurality of frequency devices.