diff --git a/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs b/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
index b7634a9..a7f6796 100644
--- a/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
+++ b/RhSolutions.AddIn/AddIn/RhSolutionsAddIn.cs
@@ -25,7 +25,7 @@ public sealed class RhSolutionsAddIn : IExcelAddIn
             .AddSingleton<IAddInConfiguration, AddInConfiguration>()
             .AddSingleton<IDatabaseClient, DatabaseClient>()
             .AddSingleton<ICurrencyClient, CurrencyClient>()
-            .AddSingleton<ISleevesCalculator, SleevesCalculator>()
+            .AddSingleton<IFittingsCalculator, SleevesCalculator>()
             .AddTransient<IFileDialog, FileDialog>();
 
         Services.AddSingleton<WriterFactory>();
diff --git a/RhSolutions.AddIn/Services/CouplingsCalculator.cs b/RhSolutions.AddIn/Services/CouplingsCalculator.cs
new file mode 100644
index 0000000..9ff4a98
--- /dev/null
+++ b/RhSolutions.AddIn/Services/CouplingsCalculator.cs
@@ -0,0 +1,9 @@
+namespace RhSolutions.Services;
+
+public class CouplingsCalculator : IFittingsCalculator
+{
+    public Dictionary<Product, double> Calculate(Dictionary<Product, double> products)
+    {
+        throw new NotImplementedException();
+    }
+}
diff --git a/RhSolutions.AddIn/Services/IFittingsCalculator.cs b/RhSolutions.AddIn/Services/IFittingsCalculator.cs
new file mode 100644
index 0000000..ffead2b
--- /dev/null
+++ b/RhSolutions.AddIn/Services/IFittingsCalculator.cs
@@ -0,0 +1,6 @@
+namespace RhSolutions.Services;
+
+public interface IFittingsCalculator
+{
+    public Dictionary<Product, double> Calculate(Dictionary<Product, double> products);
+}
diff --git a/RhSolutions.AddIn/Services/ISleevesCalculator.cs b/RhSolutions.AddIn/Services/ISleevesCalculator.cs
deleted file mode 100644
index eba37df..0000000
--- a/RhSolutions.AddIn/Services/ISleevesCalculator.cs
+++ /dev/null
@@ -1,6 +0,0 @@
-namespace RhSolutions.Services;
-
-public interface ISleevesCalculator
-{
-    public Dictionary<Product, double> CalculateSleeves(Dictionary<Product, double> products);
-}
diff --git a/RhSolutions.AddIn/Services/SleevesCalculator.cs b/RhSolutions.AddIn/Services/SleevesCalculator.cs
index acd9336..84dcbbb 100644
--- a/RhSolutions.AddIn/Services/SleevesCalculator.cs
+++ b/RhSolutions.AddIn/Services/SleevesCalculator.cs
@@ -2,14 +2,14 @@
 
 namespace RhSolutions.Services;
 
-public class SleevesCalculator : ISleevesCalculator
+public class SleevesCalculator : IFittingsCalculator
 {
     private const string doublePattern =
         @"((?i)равнопроходная|угольник\s+90|угольник\s+45|Т-образная|Комплект\s+трубок(?i))(.+?\b(?<Sleeve>16|20|25|32|40|50|63)\b)+";
     private const string singlePattern =
         @"((?i)муфта|тройник|переходник|угольник|штуцер|Г-образная|заглушка(?i))(.+?\b(?<Sleeve>16|20|25|32|40|50|63)\b)+";
 
-    public Dictionary<Product, double> CalculateSleeves(Dictionary<Product, double> products)
+    public Dictionary<Product, double> Calculate(Dictionary<Product, double> products)
     {
         Dictionary<string, double> result = new()
         {
diff --git a/RhSolutions.AddIn/Tools/SleevesTool.cs b/RhSolutions.AddIn/Tools/SleevesTool.cs
index c43bc6c..26fa0ee 100644
--- a/RhSolutions.AddIn/Tools/SleevesTool.cs
+++ b/RhSolutions.AddIn/Tools/SleevesTool.cs
@@ -2,9 +2,9 @@
 
 internal class SleevesTool : Tool
 {
-    private readonly ISleevesCalculator _sleevesCaluculator;
+    private readonly IFittingsCalculator _sleevesCaluculator;
 
-    public SleevesTool(ReaderFactory readerFactory, WriterFactory writerFactory, ISleevesCalculator sleevesCaluculator) : base(readerFactory, writerFactory)
+    public SleevesTool(ReaderFactory readerFactory, WriterFactory writerFactory, IFittingsCalculator sleevesCaluculator) : base(readerFactory, writerFactory)
     {
         _sleevesCaluculator = sleevesCaluculator;
     }
@@ -15,7 +15,7 @@ internal class SleevesTool : Tool
         Worksheet worksheet = app.ActiveWorkbook.ActiveSheet;
         _reader = _readerFactory.GetReader("Excel");
         var products = _reader.ReadProducts(new[] { worksheet });
-        var sleeves = _sleevesCaluculator.CalculateSleeves(products.Select(p => p.Item2).First());
+        var sleeves = _sleevesCaluculator.Calculate(products.Select(p => p.Item2).First());
         _writer = _writerFactory.GetWriter("CurrentPrice");
         _writer.WriteProducts(sleeves);
     }
diff --git a/RhSolutions.AddIn/Tools/ToolFactory.cs b/RhSolutions.AddIn/Tools/ToolFactory.cs
index 1c71042..bdc9bf9 100644
--- a/RhSolutions.AddIn/Tools/ToolFactory.cs
+++ b/RhSolutions.AddIn/Tools/ToolFactory.cs
@@ -4,7 +4,7 @@ internal class ToolFactory
 {
     static ReaderFactory readerFactory = RhSolutionsAddIn.ServiceProvider.GetService<ReaderFactory>();
     static WriterFactory writerFactory = RhSolutionsAddIn.ServiceProvider.GetService<WriterFactory>();
-    static ISleevesCalculator sleevesCaluculator = RhSolutionsAddIn.ServiceProvider.GetService<ISleevesCalculator>();
+    static IFittingsCalculator sleevesCaluculator = RhSolutionsAddIn.ServiceProvider.GetService<IFittingsCalculator>();
 
     public Tool GetTool(string toolName)
     {
diff --git a/RhSolutions.Tests/CanFillSleeves.cs b/RhSolutions.Tests/CanFillSleeves.cs
index aedad09..ca00407 100644
--- a/RhSolutions.Tests/CanFillSleeves.cs
+++ b/RhSolutions.Tests/CanFillSleeves.cs
@@ -6,7 +6,7 @@ namespace RhSolutions.Tests;
 public class CanFillSleeves : IDisposable
 {
     private RhSolutionsAddIn _addIn;
-    private ISleevesCalculator _calculator;
+    private IFittingsCalculator _calculator;
     private IReader _reader;
     private IWriter _writer;
     private Worksheet _worksheet;
@@ -25,7 +25,7 @@ public class CanFillSleeves : IDisposable
     public void CanCalculateSleeves()
     {
         var products = _reader.ReadProducts(new[] { _worksheet });
-        var sleeves = _calculator.CalculateSleeves(products.First().Item2);
+        var sleeves = _calculator.Calculate(products.First().Item2);
         _writer.WriteProducts(sleeves);
 
         Assert.Equal(25, _worksheet.Range["E2"].Value);