diff --git a/.github/workflows/c-cpp.yml b/.github/workflows/c-cpp.yml
index 8ab8512..d3b428b 100644
--- a/.github/workflows/c-cpp.yml
+++ b/.github/workflows/c-cpp.yml
@@ -11,19 +11,27 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ubuntu-22.04]
-        cxx: [g++-12, g++-11, clang++-15, clang++-14]
+        os: [ubuntu-22.04, ubuntu-24.04]
+        cxx: [g++-14, g++-13, g++-12, g++-11, clang++-18, clang++-17, clang++-16, clang++-15 ]
         include:
           - os: macos-latest
             cxx: clang++
-          - os: ubuntu-24.04
-            cxx: g++-13
-          - os: ubuntu-24.04
+        exclude:
+          - os: ubuntu-22.04
             cxx: clang++-16
-          - os: ubuntu-24.04
+          - os: ubuntu-22.04
             cxx: clang++-17
-          - os: ubuntu-24.04
+          - os: ubuntu-22.04
             cxx: clang++-18
+          - os: ubuntu-22.04
+            cxx: g++-13
+          - os: ubuntu-22.04
+            cxx: g++-14
+
+          - os: ubuntu-24.04
+            cxx: clang++-15
+          - os: ubuntu-24.04
+            cxx: g++-11
 
     runs-on: ${{ matrix.os }}
 
diff --git a/tests/callable_tests.cc b/tests/callable_tests.cc
index a726b0b..860e7b7 100644
--- a/tests/callable_tests.cc
+++ b/tests/callable_tests.cc
@@ -48,3 +48,91 @@ TEST_CASE("Callable Function lots of params") {
 	CHECK(func(10, 10.f, 'a', {}, {2, 'a', 1.2f, 1.4}) == 137);
 	CHECK(capture == 20);
 }
+
+TEST_CASE("FunctionSized") {
+	// This fails to compile (which is what we want)
+	// auto capture{0};
+	// auto capture2{0};
+	// auto capture3{0};
+	// auto func = Function<int(int, int)>{[&](int a, int b) {
+	// 	capture += 10;
+	// 	capture2 += 10;
+	// 	capture3 += 10;
+	// 	return a + b + capture;
+	// }};
+
+	auto capture{0};
+	auto capture2{0};
+	auto capture3{0};
+	auto func = FunctionSized<sizeof(void *) * 3, int(int, int)>{[&](int a, int b) {
+		capture += 10;
+		capture2 += 10;
+		capture3 += 10;
+		return a + b + capture;
+	}};
+}
+
+TEST_CASE("Callable") {
+	auto capture{0};
+
+	auto func = Callback{[&capture] {
+		capture += 10;
+		return capture;
+	}};
+
+	func();
+	CHECK(capture == 10);
+	func();
+	CHECK(capture == 20);
+}
+
+TEST_CASE("CallableSized") {
+	auto capture{0};
+	auto capture2{0};
+	auto capture3{0};
+
+	auto func = CallbackSized<sizeof(void *) * 3>{[&] {
+		capture += 10;
+		capture2 += 10;
+		capture3 += 10;
+		return capture;
+	}};
+
+	func();
+	CHECK(capture3 == 10);
+	func();
+	CHECK(capture3 == 20);
+}
+
+TEST_CASE("~Callable") {
+	auto capture{0};
+
+	Callback *func = new Callback{[&capture] {
+		capture += 10;
+		return capture;
+	}};
+
+	(*func)();
+	CHECK(capture == 10);
+	(*func)();
+	CHECK(capture == 20);
+
+	delete func;
+
+	Callback *empty = new Callback();
+	delete empty;
+}
+
+TEST_CASE("operator bool") {
+	auto capture{0};
+
+	Callback func;
+	CHECK_FALSE((bool)func);
+
+	func = Callback{[&capture] {
+		capture += 10;
+		return capture;
+	}};
+
+	CHECK((bool)func);
+}
diff --git a/util/callable.hh b/util/callable.hh
index 91b4431..7648757 100644
--- a/util/callable.hh
+++ b/util/callable.hh
@@ -13,110 +13,48 @@
 // (which shouldn't happen, since the point of this is to avoid the heap,
 // but it could...)
 
-template<unsigned BUFFER_SIZE = 2 * sizeof(void *)>
-class CallbackSized {
-private:
-	// static constexpr unsigned BUFFER_SIZE = 2 * sizeof(void *);
-
-public:
-	CallbackSized() = default;
-
-	template<typename Callable>
-	CallbackSized(Callable callable) {
-		static_assert(sizeof(Callable) <= BUFFER_SIZE);
-		static_assert(std::is_invocable_v<Callable>);
-
-		new (&m_data[0]) Callable(callable);
-		m_callback = invoke<Callable>;
-		m_destroy = destroy<Callable>;
-	}
-
-	~CallbackSized() {
-		if (m_destroy)
-			m_destroy(&m_data[0]);
-	}
-
-	void call() {
-		// if (m_callback)
-		m_callback(&m_data[0]);
-		return;
-	}
-
-	void operator()() {
-		call();
-	}
-
-	operator bool() {
-		return m_callback;
-	}
-
-private:
-	template<typename Callable>
-	static void invoke(void *object) {
-		Callable &callable = *reinterpret_cast<Callable *>(object);
-		callable();
-	}
-
-	template<typename Callable>
-	static void destroy(void *object) {
-		Callable &callable = *reinterpret_cast<Callable *>(object);
-		callable.~Callable();
-	}
-
-private:
-	using CallbackM = void (*)(void *);
-	CallbackM m_callback{};
-
-	using Deleter = void (*)(void *);
-	Deleter m_destroy{};
-
-	alignas(uint64_t) uint8_t m_data[BUFFER_SIZE];
-};
-
-using Callback = CallbackSized<2 * sizeof(void *)>;
-
 // Function<T> is a callback that takes parameters and returns something
-template<typename Signature>
-struct Function {};
-
-template<typename Ret, typename... Args>
-class Function<Ret(Args...)> {
-private:
-	static constexpr uint8_t BUFFER_SIZE = 2 * sizeof(void *);
+template<unsigned buffer_size, typename Signature>
+struct FunctionSized {};
 
+template<unsigned buffer_size, typename Ret, typename... Args>
+class FunctionSized<buffer_size, Ret(Args...)> {
 public:
-	Function() = default;
+	FunctionSized() = default;
 
 	template<typename Callable>
-	Function(Callable callable) {
-		static_assert(sizeof(Callable) <= BUFFER_SIZE);
-		static_assert(std::is_invocable_v<Callable, Args...>);
-
+	requires(sizeof(Callable) <= buffer_size && std::is_invocable_v<Callable, Args...>)
+	FunctionSized(Callable callable)
+		: m_callback{invoke<Callable>}
+		, m_destroy{destroy<Callable>} {
 		new (&m_data[0]) Callable(callable);
-		m_callback = invoke<Callable>;
-		m_destroy = destroy<Callable>;
 	}
 
-	~Function() {
+	~FunctionSized() {
 		if (m_destroy)
 			m_destroy(&m_data[0]);
 	}
 
 	Ret call(Args... args) {
-		if (m_callback)
-			return m_callback(&m_data[0], std::forward<Args>(args)...);
-		return Ret();
+		return m_callback(&m_data[0], std::forward<Args>(args)...);
 	}
 
 	Ret operator()(Args... args) {
 		return call(std::forward<Args>(args)...);
 	}
 
+	operator bool() const {
+		return m_callback;
+	}
+
 private:
 	template<typename Callable>
 	static Ret invoke(void *object, Args... args) {
 		Callable &callable = *reinterpret_cast<Callable *>(object);
-		return callable(std::forward<Args>(args)...);
+		if constexpr (std::is_same_v<void, Ret>)
+			callable(std::forward<Args>(args)...);
+		else
+			return callable(std::forward<Args>(args)...);
 	}
 
 	template<typename Callable>
@@ -132,5 +70,13 @@ private:
 	using Deleter = void (*)(void *);
 	Deleter m_destroy{};
 
-	alignas(uint64_t) uint8_t m_data[BUFFER_SIZE];
+	alignas(uint64_t) uint8_t m_data[buffer_size];
 };
+
+template<typename Signature>
+using Function = FunctionSized<sizeof(void *) * 2, Signature>;
+
+template<unsigned size = sizeof(void *) * 2>
+using CallbackSized = FunctionSized<size, void(void)>;
+
+using Callback = CallbackSized<2 * sizeof(void *)>;