diff --git a/Snail/Unique.swift b/Snail/Unique.swift
index 37d82f0..9e4b19b 100644
--- a/Snail/Unique.swift
+++ b/Snail/Unique.swift
@@ -22,4 +22,10 @@ public class Unique<T: Equatable>: Variable<T> {
         super.init(value)
         subject.on(.next(value))
     }
+
+    public override func map<U>(transform: @escaping (T) -> U) -> Unique<U> {
+        let newVariable = Unique<U>(transform(value))
+        asObservable().subscribe(onNext: { _ in newVariable.value = transform(self.value) })
+        return newVariable
+    }
 }
diff --git a/Snail/Variable.swift b/Snail/Variable.swift
index 56376c3..57bb92e 100644
--- a/Snail/Variable.swift
+++ b/Snail/Variable.swift
@@ -31,8 +31,8 @@ public class Variable<T> {
         return subject
     }
 
-    public func map<U>(transform: @escaping (T) -> U) -> Unique<U> {
-        let newVariable = Unique<U>(transform(value))
+    public func map<U>(transform: @escaping (T) -> U) -> Variable<U> {
+        let newVariable = Variable<U>(transform(value))
         asObservable().subscribe(onNext: { _ in newVariable.value = transform(self.value) })
         return newVariable
     }
diff --git a/SnailTests/VariableTests.swift b/SnailTests/VariableTests.swift
index 7530d9d..d6c596a 100644
--- a/SnailTests/VariableTests.swift
+++ b/SnailTests/VariableTests.swift
@@ -64,4 +64,41 @@ class VariableTests: XCTestCase {
 
         XCTAssertEqual(subject.value.count, subjectCharactersCount)
     }
+
+    func testUniqueFireCounts() {
+        let subject = Unique("one")
+        var firedCount = 0
+
+        subject.map { $0.count }.asObservable().subscribe(onNext: { _ in
+            firedCount += 1
+        })
+
+        subject.value = "two"
+
+        XCTAssertTrue(firedCount == 1)
+    }
+
+    func testVariableFireCounts() {
+        let subject = Variable("one")
+        var firedCount = 0
+
+        subject.map { $0.count }.asObservable().subscribe(onNext: { _ in
+            firedCount += 1
+        })
+
+        subject.value = "two"
+
+        XCTAssertTrue(firedCount == 2)
+    }
+
+    func testMapToVoid() {
+        let subject = Variable("initial")
+        var fired = false
+
+        subject.map { _ in return () }.asObservable().subscribe(onNext: { _ in
+            fired = true
+        })
+
+        XCTAssertTrue(fired)
+    }
 }