39. The improvement of claim 37 , wherein the closure has a first top surface with a first drive feature and the set screw has a second central portion with a second drive feature.
39. The improvement of claim 37 , wherein the closure has a first top surface with a first drive feature and the set screw has a second central portion with a second drive feature. 41. The improvement of claim 39 , wherein the second drive feature is multi-lobular.