an assembly for inserting an attachment coil in concrete with a screw having a releasable spacer and an expandable coil mounted thereon . the spacer initially positions the screw in a hole for location of the coil and has a slot to permit the spacer to pop off the screw as the screw is screwed into the coil in the hole . the spacer may have longitudinal ribs to bridge any lateral space between the screw and the hole . the coil has an exterior diameter less than the interior diameter of the hole for free movement of unexpanded loops without creating cross threading during insertion . a second coil can be inserted closer to the surface by assembling two spacers on a screw for location of the second coil , with both spacers popping off the screw as the screw advances into both coils . the use of two coils in a hole allows positioning of coils in both compression and tension zones on opposite sides of a neutral axis of the structure . a sealing compound may be inserted in the hole after removing a screw following insertion of a coil and then reinserting the screw to compress the sealing compound fully within the hole .