These fasteners are intended for general use in aircraft to secure electronic LRUs in their installed position. They are designed with knurled or fluted knobs for hand operation to:

a. Eliminate the need to have hand tools available and

b. Reduce the risk of overstressing the LRU, rack, tray or other fastener accessories. The fastener must be used in conjunction with rear holddown device with properly toleranced, dimensionally stable seating that positions the front fasteners so as to give proper load line angle (see applicable specification sheet).

These fasteners are intended for use in military aircraft. Their purpose is to secure electronic LRUs installed in compliance with DOD-STD-1788 Avionics Interface Design Standard, and for use with commercial avionics LRUs that are designed in compliance with ARINC specification 600. They are designed for hand operation through a calibrated, force-limiting clutch in the forward direction (insertion). When operated in the reverse direction (extraction) they withdraw the LRU from its mounting rack or tray, disengaging the rear-mounted connector with a controlled straight pull. In these applications, the connector shell is the rear holddown, with a properly toleranced, dimensionally stable, rack or tray to ensure that the front fasteners are correctly positioned.

There shall be some form of clear visual indication that the extractor front holddown unit has been activated to its designated load (refer to MIL-F-85731/2).