diff --git a/NanoVNASaver/RFTools.py b/NanoVNASaver/RFTools.py
index 6debc82..c69086e 100644
--- a/NanoVNASaver/RFTools.py
+++ b/NanoVNASaver/RFTools.py
@@ -16,9 +16,9 @@
 #  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import math
 import cmath
-from numbers import Number, Real
+from numbers import Number
 from typing import List, NamedTuple
-from NanoVNASaver.SITools import Value, Format
+from NanoVNASaver.SITools import Value, Format, clamp_value
 
 FMT_FREQ = Format()
 FMT_SHORT = Format(max_nr_digits=4)
@@ -123,15 +123,6 @@ class Datapoint(NamedTuple):
             self.impedance(ref_impedance), self.freq)
 
 
-def clamp_value(value: Real, rmin: Real, rmax: Real) -> Real:
-    assert rmin <= rmax
-    if value < rmin:
-        return rmin
-    if value > rmax:
-        return rmax
-    return value
-
-
 def groupDelay(data: List[Datapoint], index: int) -> float:
     idx0 = clamp_value(index - 1, 0, len(data) - 1)
     idx1 = clamp_value(index + 1, 0, len(data) - 1)
diff --git a/NanoVNASaver/SITools.py b/NanoVNASaver/SITools.py
index cbc198d..d442be7 100644
--- a/NanoVNASaver/SITools.py
+++ b/NanoVNASaver/SITools.py
@@ -3,7 +3,7 @@
 #  Copyright (C) 2019.  Rune B. Broberg
 #
 #  This program is free software: you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
+#  it under the terms of the GNU General Public License as published bynanovna
 #  the Free Software Foundation, either version 3 of the License, or
 #  (at your option) any later version.
 #
@@ -18,12 +18,21 @@ from __future__ import annotations
 import math
 import decimal
 from typing import NamedTuple, Union
-from numbers import Number
+from numbers import Number, Real
 
 PREFIXES = ("y", "z", "a", "f", "p", "n", "µ", "m",
             "", "k", "M", "G", "T", "P", "E", "Z", "Y")
 
 
+def clamp_value(value: Real, rmin: Real, rmax: Real) -> Real:
+    assert rmin <= rmax
+    if value < rmin:
+        return rmin
+    if value > rmax:
+        return rmax
+    return value
+
+
 class Format(NamedTuple):
     max_nr_digits: int = 6
     fix_decimals: bool = False
@@ -144,12 +153,9 @@ class Value:
                                decimal.Decimal(factor, context=Value.CTX))
             except decimal.InvalidOperation:
                 raise ValueError
-            # TODO: get formating out of RFTools to be able to import clamp
-            #       and reuse code
-            if self._value < self.fmt.parse_clamp_min:
-                self._value = self.fmt.parse_clamp_min
-            elif self._value > self.fmt.parse_clamp_max:
-                self._value = self.fmt.parse_clamp_max
+            self._value = clamp_value(self._value,
+                                      self.fmt.parse_clamp_min,
+                                      self.fmt.parse_clamp_max)
         return self
 
     @property