Detachable coil incorporating stretch resistance

An implant delivery system, comprising:

• a pusher;
• an embolic coil;
• and
• a tether connected to the pusher and the embolic coil,
• wherein the tether is wrapped around at an attachment portion of the embolic coil,
• wherein a first portion of the tether proximal to the attachment portion of the embolic coil has a first tension, and
• wherein a second portion of the tether distal to the attachment portion of the embolic coil has a second tension different from the first tension.

An implant delivery system, comprising:

• a tether coupled to a pusher;
• an embolic coil;
• and
• attaching means for attaching the tether to at least two winds of the embolic coil, wherein a distal portion of the tether that is distal to the at least two winds of the embolic coil has a first tension, and wherein a proximal portion of the tether that is proximal to the at least two winds of the embolic coil has a second tension different from the first tension.