diff --git a/Grid/lattice/Lattice_slicesum_core.h b/Grid/lattice/Lattice_slicesum_core.h
index 5d96c4fb..f3bd51ad 100644
--- a/Grid/lattice/Lattice_slicesum_core.h
+++ b/Grid/lattice/Lattice_slicesum_core.h
@@ -59,7 +59,7 @@ inline void sliceSumReduction_cub_small(const vobj *Data,
 #if defined(__CUDACC__) && (__CUDACC_VER_MAJOR__ >= 13)
   #define GRID_CUB_SUM_OP ::cuda::std::plus<>{}
 #else
-  #define GRID_CUB_SUM_OP ::cub::Sum()
+  #define GRID_CUB_SUM_OP ::gpucub::Sum()
 #endif
   
   gpuError_t gpuErr = gpucub::DeviceSegmentedReduce::Reduce(temp_storage_array, temp_storage_bytes, rb_p,d_out, rd, d_offsets, d_offsets+1, GRID_CUB_SUM_OP, zero_init, computeStream);