Inventory The Inventory tab allows you to view inventory information about the OPT-BST, OPT-BST-L, OPT-PRE, OPT-AMP-L, OPT-AMP-C, and OPT-AMP-17-C cards. Item Description Attribute Displays the name of the attribute. Value Displays the value or version of the attribute. Units Displays the unit of measurement, if applicable, of the attribute. Help Displays context-sensitive help.