An apparatus comprises a first end and a second end opposite the first end. A first leg comprising a first surface and a second surface is disposed between the first and second ends. A second leg comprising a first surface and a second surface is disposed between the first and second ends. A first receiving groove is disposed in the first leg and forms a first pathway. A second receiving groove is disposed in the second leg and forms a second pathway. A first receiving channel is disposed in the first leg and is in communication with the first receiving groove. A second receiving channel is disposed in the second leg and is in communication with the second receiving groove. A fin is coupled to the first and second legs and is disposed between the first and second receiving channels. The fin is substantially coplanar with the first end.