An occlusive implant can be delivered into a body vessel using a delivery assembly that can engage with at least a portion of the implant. The assembly can utilize an engagement member and an engagement socket or a catheter or sheath to removably couple the engagement member with the implant. When the implant is advanced to a target location in the body vessel, the implant can be released to restrict flow of a fluid through the vessel and/or promote occlusion of the vessel.