diff --git a/src/activities/Elsa.Activities.Http/Models/StringValuesModel.cs b/src/activities/Elsa.Activities.Http/Models/StringValuesModel.cs
index 71fe2125b..c9fb296e4 100644
--- a/src/activities/Elsa.Activities.Http/Models/StringValuesModel.cs
+++ b/src/activities/Elsa.Activities.Http/Models/StringValuesModel.cs
@@ -1,33 +1,84 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using Microsoft.Extensions.Primitives;
 
 namespace Elsa.Activities.Http.Models
 {
-    public class StringValuesModel
+    /// <summary>
+    /// Represents a collection of zero or more string values.  It is used for values such as
+    /// HTTP header/query string values.  These are often thought-of as key/value pairs but might
+    /// have more than one value.
+    /// </summary>
+    public class StringValuesModel : IConvertible
     {
-        public string? Value { get; set; }
-        public string[]? Values { get; set; }
+        /// <summary>
+        /// Gets either the first value of <see cref="Values"/> or a <see langword="null"/> reference
+        /// if the values are null or empty.
+        /// </summary>
+        /// <returns>The first value</returns>
+        public string? Value => Values?.FirstOrDefault();
 
-        public StringValuesModel()
-        {
-        }
+        /// <summary>
+        /// Gets a collection of the string values for the current instance.
+        /// </summary>
+        /// <value>The values</value>
+        public string[] Values { get; set; }
 
-        public StringValuesModel(StringValues value)
-        {
-            Value = value.Count == 1 ? value.ToString() : default;
-            Values = value.Count != 1 ? value.ToArray() : default;
-        }
+        /// <summary>
+        /// Initializes an instance of <see cref="StringValuesModel"/> with an empty collection of values.
+        /// </summary>
+        public StringValuesModel() => Values = new string[0];
 
-        public override string? ToString()
-        {
-            if (Values == null)
-                return Value;
+        /// <summary>
+        /// Initializes an instance of <see cref="StringValuesModel"/> from a <see cref="StringValues"/>.
+        /// </summary>
+        /// <param name="value">A model of zero or more string values.</param>
+        public StringValuesModel(StringValues value) => Values = value.ToArray();
 
-            return Values.Length switch
-            {
-                0 => default,
-                1 => Values[0],
-                _ => string.Join(",", Values)
-            };
-        }
+        /// <summary>
+        /// Gets a string representation of the current instance.  Either null (for no, or an empty-collection of <see cref="Values"/>),
+        /// a single string (for a collection of one <see cref="Values"/>) or a comma-separated string of many values.
+        /// </summary>
+        /// <returns>The string representation of the <see cref="Values"/>.</returns>
+        public override string? ToString() => (Values?.Any() == true) ? string.Join(",", Values) : null;
+
+        #region IConvertible implementation
+
+        TypeCode IConvertible.GetTypeCode() => TypeCode.Object;
+
+        bool IConvertible.ToBoolean(IFormatProvider provider) => Convert.ToBoolean(ToString(), provider);
+
+        byte IConvertible.ToByte(IFormatProvider provider) => Convert.ToByte(ToString(), provider);
+
+        char IConvertible.ToChar(IFormatProvider provider) => Convert.ToChar(ToString(), provider);
+
+        DateTime IConvertible.ToDateTime(IFormatProvider provider) => Convert.ToDateTime(ToString(), provider);
+
+        decimal IConvertible.ToDecimal(IFormatProvider provider) => Convert.ToDecimal(ToString(), provider);
+
+        double IConvertible.ToDouble(IFormatProvider provider) => Convert.ToDouble(ToString(), provider);
+
+        short IConvertible.ToInt16(IFormatProvider provider) => Convert.ToInt16(ToString(), provider);
+
+        int IConvertible.ToInt32(IFormatProvider provider) => Convert.ToInt32(ToString(), provider);
+
+        long IConvertible.ToInt64(IFormatProvider provider) => Convert.ToInt64(ToString(), provider);
+
+        sbyte IConvertible.ToSByte(IFormatProvider provider) => Convert.ToSByte(ToString(), provider);
+
+        float IConvertible.ToSingle(IFormatProvider provider) => Convert.ToSingle(ToString(), provider);
+
+        string IConvertible.ToString(IFormatProvider provider) => ToString()!;
+
+        object IConvertible.ToType(Type conversionType, IFormatProvider provider) => Convert.ChangeType(ToString(), conversionType, provider);
+
+        ushort IConvertible.ToUInt16(IFormatProvider provider) => Convert.ToUInt16(ToString(), provider);
+
+        uint IConvertible.ToUInt32(IFormatProvider provider) => Convert.ToUInt32(ToString(), provider);
+
+        ulong IConvertible.ToUInt64(IFormatProvider provider) => Convert.ToUInt64(ToString(), provider);
+
+        #endregion
     }
 }
\ No newline at end of file
diff --git a/test/unit/Elsa.UnitTests/Activities/Http/StringValuesModelTests.cs b/test/unit/Elsa.UnitTests/Activities/Http/StringValuesModelTests.cs
new file mode 100644
index 000000000..c61ef147b
--- /dev/null
+++ b/test/unit/Elsa.UnitTests/Activities/Http/StringValuesModelTests.cs
@@ -0,0 +1,96 @@
+using System;
+using Elsa.Activities.Http.Models;
+using Microsoft.Extensions.Primitives;
+using Xunit;
+
+namespace Elsa.Activities.Http
+{
+    public class StringValuesModelTests
+    {
+        [Theory(DisplayName = "It should be possible to use Convert.ChangeType to convert an instance to string.  This is primarily to support usage via Jint."), AutoMoqData]
+        public void ItShouldBePossibleToConvertAStringValuesModelToString(string[] values)
+        {
+            var sut = new StringValuesModel(new StringValues(values));
+            var result = Convert.ChangeType(sut, typeof(string));
+            Assert.Equal(sut.ToString(), result);
+        }
+
+        [Theory(DisplayName = "It should be possible to use Convert.ToInt32 to convert an instance to a number if the value is a valid string representation of a number.  This is primarily to support usage via Jint."), AutoMoqData]
+        public void ItShouldBePossibleToConvertAStringValuesModelToInt32IfValid()
+        {
+            var sut = new StringValuesModel(new StringValues("3"));
+            var result = Convert.ChangeType(sut, typeof(int));
+            Assert.Equal(3, result);
+        }
+
+        [Theory(DisplayName = "The Value property should return the first value if there is more than one."), AutoMoqData]
+        public void ValueShouldReturnFirstItemIfThereAreMoreThanOne(string firstValue, string secondValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue, secondValue }));
+            Assert.Equal(firstValue, sut.Value);
+        }
+
+        [Theory(DisplayName = "The Value property should always return the first value if there is only one."), AutoMoqData]
+        public void ValueShouldReturnFirstItemIfThereIsOne(string firstValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue }));
+            Assert.Equal(firstValue, sut.Value);
+        }
+
+        [Fact(DisplayName = "The Value property should return null if there are no values.")]
+        public void ValueShouldReturnNullIfThereAreNone()
+        {
+            var sut = new StringValuesModel(new StringValues(new string[0]));
+            Assert.Null(sut.Value);
+        }
+
+        [Theory(DisplayName = "The Values property should return a length-one collection if there is a single value."), AutoMoqData]
+        public void ValuesShouldReturnLengthOneCollectionIfThereIsOneValue(string firstValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue }));
+            Assert.Equal(new [] {firstValue}, sut.Values);
+        }
+
+        [Theory(DisplayName = "The Values property should return a length-two collection if there are two values."), AutoMoqData]
+        public void ValuesShouldReturnLengthTwoCollectionIfThereAreTwoValues(string firstValue, string secondValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue, secondValue }));
+            Assert.Equal(new [] {firstValue, secondValue}, sut.Values);
+        }
+
+        [Fact(DisplayName = "The Values property should return an empty collection if there are no values.")]
+        public void ValuesShouldReturnEmptyCollectionIfThereAreNone()
+        {
+            var sut = new StringValuesModel(new StringValues(new string[0]));
+            Assert.Empty(sut.Values);
+        }
+
+        [Fact(DisplayName = "The ToString method should return null if there are no values")]
+        public void ToStringShouldReturnNullIfNotValues()
+        {
+            var sut = new StringValuesModel(new StringValues(new string[0]));
+            Assert.Null(sut.ToString());
+        }
+
+        [Theory(DisplayName = "The ToString method should return the first value if there is only one"), AutoMoqData]
+        public void ToStringShouldReturnFirstValueIfThereIsOnlyOne(string firstValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue }));
+            Assert.Equal(firstValue, sut.ToString());
+        }
+
+        [Theory(DisplayName = "The ToString method should return comma-separated values if there are more than one"), AutoMoqData]
+        public void ToStringShouldReturnCommaSeparatedValuesIfThereIsMoreThanOne(string firstValue, string secondValue)
+        {
+            var sut = new StringValuesModel(new StringValues(new [] { firstValue, secondValue }));
+            Assert.Equal($"{firstValue},{secondValue}", sut.ToString());
+        }
+
+        [Fact(DisplayName = "The parameterless constructor should initialize Values to an empty collection")]
+        public void ParameterlessCtorShouldInitializeWithEmptyCollection()
+        {
+            var sut = new StringValuesModel();
+            Assert.Empty(sut.Values);
+        }
+    }
+}
\ No newline at end of file