Abstract: A multi-component kit for a curable composition for fixing purposes, comprising an epoxy component (a), which comprises curable epoxides, and a hardener component (b), which comprises a Mannich base formulation, and the use of Mannich base formulations and, especially, further additives in hardener components for epoxy resins, the Mannich base formulation having specific properties (viscosity, H equivalents, content of free phenol derivatives). The multi-component kits according to the invention can be used within a broad temperature range and enable mortar compositions to be produced which, after curing, exhibit a particularly large tolerance range for temperatures and exhibit particularly high bond stress values at low temperatures and, especially, also at high temperatures.