The T Series was designed to be used as a cap or a plug and are tapered to fit a wide range of applications to protect from contaminants and debris. These caps/plugs may be used for mil Std, sae-type fittings, hydraulic and threaded or non threaded fittings. The tapered design allows the opportunity to cover a vast range of cap or plug applications. Easy to install or remove.:: a: 1.276, b: 1.312, C: 1.155, D: 1.19, E: 0.5, F: 1.38.