This is the Optically-Flat Sapphire Assembly Replacement for the Agilent Variable Leak Valve (PN: 951-5106). The sapphire assembly is designed to be replaced using a special removal tool, also made by Agilent. The assembly should arrive without any chips, scratches or cracks to ensure proper operation of the Agilent Variable Leak Valve. We offer all the necessary tools to make repairs and adjustments to the variable leak valve in our Related Products section below, including replacement parts such as the complete repair/tool kit and gasket assemblies. Replacement Sapphire Assembly, PN 9530072