diff --git a/code/lattice.f90 b/code/lattice.f90
index a806d68a5..4709d3612 100644
--- a/code/lattice.f90
+++ b/code/lattice.f90
@@ -688,7 +688,7 @@ module lattice
      20,20,20,20,20,20,  19,19,19,19,19,19,  18,18,18,18,18,18,  17,17,16,17,17,17, &
      20,20,20,20,20,20,  19,19,19,19,19,19,  18,18,18,18,18,18,  17,17,17,16,17,17, &
      20,20,20,20,20,20,  19,19,19,19,19,19,  18,18,18,18,18,18,  17,17,17,17,16,17, &
-     20,20,20,20,20,20,  19,19,19,19,19,19,  18,18,18,18,18,18,  17,17,17,17,17, 4  &
+     20,20,20,20,20,20,  19,19,19,19,19,19,  18,18,18,18,18,18,  17,17,17,17,17,16  &
      ],pInt),[lattice_hex_Ntwin,lattice_hex_Ntwin],order=[2,1])                                     !< Twin--slip interaction types for hex (isotropic, 16 in total)