Interscrews, although being a special range of fasteners these have been requested from us under a variety of names :-
Socket Nuts, Tube Nuts, Connector Bolts, Clamp Bolts, Sex Bolts, Barrel Nuts, Screws with Internal Threads, Sleeve Nuts etc
In many cases they have been be used as a single unit with a mating screw or in pairs with a threaded stud which can greatly extend the available grip range.