diff --git a/src/dftbp/dftbplus/inputdata.F90 b/src/dftbp/dftbplus/inputdata.F90
index 7bcc37a6eb..c243bc9c27 100644
--- a/src/dftbp/dftbplus/inputdata.F90
+++ b/src/dftbp/dftbplus/inputdata.F90
@@ -335,6 +335,8 @@ module dftbp_dftbplus_inputdata
 
     !> Whether to initialize internal state of the Nose-Hoover thermostat from input
     logical :: tInitNHC = .false.
+
+    !> Internal state variables for the Nose-Hoover chain thermostat
     real(dp), allocatable :: xnose(:)
     real(dp), allocatable :: vnose(:)
     real(dp), allocatable :: gnose(:)