Apparatus is provided including a percutaneously-implantable implant and an adjustment device. The adjustment device can comprise an adjustment mechanism, coupled to the implant, and configured to change a dimension of the implant upon actuation of the adjustment mechanism and a lock. The adjustment device can have a locked state in which the lock inhibits actuation of the adjustment mechanism and an unlocked state in which the adjustment mechanism is actuatable. The adjustment device can be reversibly movable between the locked state and the unlocked state. The apparatus can include a longitudinal guide member and an adapter. An unlocking mechanism can be configured such that, while the adapter is coupled to the adjustment device, actuation of the unlocking mechanism moves the lock between the locked state and the unlocked state. Other applications are also described.
