Embolic coil implant systems whereby coils (16, 116, 216) are mechanically detachable are disclosed. The coils include a retention element (32, 132, 232) that may be releasably retained within the distal end of an implant tool (14, 114, 214). The implant tool may include a fulcrum (120) configured to engage a first filament (30) and prevent the release of the coil when the first filament is engaged. Alternatively, an urging means (240) and aperture (244) may be disposed within the sidewall of the implant tool, and a first filament may, in conjunction with the aperture and sidewall, releasably retain the coil until the first filament is withdrawn. The implant tool may also include an alignment member (228) for aligning the first filament.
