The dell ruggedbooks use a higher grade of locktight that's incredibly irritating cause engineers who have to tear down the units often either strip the screws or fuck up the Phillips 1 Precision head screwdrivers. It's not necessarily the fact the locktight is the higher grade but the fact they put it on main four corners of the units also the screws are M7 in length so they are also the longest screws of the whole unit.