A closure system for sealing an aperture in a tissue of a body lumen, the system comprising a closure device and a delivery device, wherein the delivery device has an attachment mechanism to releasably attach the closure device for delivery to an aperture in tissue and is configured to deploy the closure device within a lumen, and wherein the closure device comprises: a sealable member positionable against an interior surface of the tissue adjacent the aperture in the tissue when the device is in a sealing position; a support member comprising a base and a column, wherein the base of the support member comprises a support surface to support the sealable member against the interior surface of the tissue when the device is in the sealing position and the column extends through the sealing member and the aperture and comprises an engagement mechanism; and a locator pivotably coupled to the support member via the engagement mechanism and positionable against an exterior surface of the tissue adjacent the aperture when the device is in the sealing position, so that at least a portion of the tissue is disposed between the locator and the sealable member, wherein the locator comprises: an adjustment mechanism for accommodating varying tissue topographies,and an elongate planar body, characterized in that the locator further comprises: a non-planar distal portion comprising a first angular portion extending upwardly from the elongate body and a second angular portion extending from the first angular portion, and a guide mechanism that extends upwardly from a top surface of the locator to movably engage with the delivery device for deploying the locator. wherein the closure device comprises: a sealable member positionable against an interior surface of the tissue adjacent the aperture in the tissue when the device is in a sealing position; a support member comprising a base and a column, wherein the base of the support member comprises a support surface to support the sealable member against the interior surface of the tissue when the device is in the sealing position and the column extends through the sealing member and the aperture and comprises an engagement mechanism; and a locator pivotably coupled to the support member via the engagement mechanism and positionable against an exterior surface of the tissue adjacent the aperture when the device is in the sealing position, so that at least a portion of the tissue is disposed between the locator and the sealable member, wherein the locator comprises: an adjustment mechanism for accommodating varying tissue topographies,and an elongate planar body, a sealable member positionable against an interior surface of the tissue adjacent the aperture in the tissue when the device is in a sealing position; a support member comprising a base and a column, wherein the base of the support member comprises a support surface to support the sealable member against the interior surface of the tissue when the device is in the sealing position and the column extends through the sealing member and the aperture and comprises an engagement mechanism; and a locator pivotably coupled to the support member via the engagement mechanism and positionable against an exterior surface of the tissue adjacent the aperture when the device is in the sealing position, so that at least a portion of the tissue is disposed between the locator and the sealable member, wherein the locator comprises: an adjustment mechanism for accommodating varying tissue topographies,and an elongate planar body, an adjustment mechanism for accommodating varying tissue topographies,and an elongate planar body, characterized in that the locator further comprises: a non-planar distal portion comprising a first angular portion extending upwardly from the elongate body and a second angular portion extending from the first angular portion, and a guide mechanism that extends upwardly from a top surface of the locator to movably engage with the delivery device for deploying the locator. a non-planar distal portion comprising a first angular portion extending upwardly from the elongate body and a second angular portion extending from the first angular portion, and a guide mechanism that extends upwardly from a top surface of the locator to movably engage with the delivery device for deploying the locator.