diff --git a/src/async_utils/_qs.py b/src/async_utils/_qs.py
index 0704bac..51e4af1 100644
--- a/src/async_utils/_qs.py
+++ b/src/async_utils/_qs.py
@@ -192,156 +192,6 @@ def set(self, /) -> bool:
         return success
 
 
-class Semaphore:
-    __slots__ = (
-        "__weakref__",
-        "_unlocked",
-        "_value",
-        "_waiters",
-    )
-
-    def __init__(self, value: int = 1, /) -> None:
-        self._value: int = value
-        self._waiters: deque[AsyncEvent | ThreadingEvent] = deque()
-        self._unlocked: list[None] = [None] * self._value
-
-    async def __aenter__(self, /) -> t.Self:
-        await self.async_acquire()
-        return self
-
-    async def __aexit__(self, *dont_care: object) -> None:
-        self.release()
-
-    def __enter__(self, /) -> t.Self:
-        self.sync_acquire()
-
-        return self
-
-    def __exit__(self, *dont_care: object) -> None:
-        self.release()
-
-    def _acquire_nowait(self, /) -> bool:
-        if unlocked := self._unlocked:
-            try:
-                unlocked.pop()
-            except IndexError:
-                success = False
-            else:
-                success = True
-        else:
-            success = False
-
-        return success
-
-    async def async_acquire(self) -> bool:
-        waiters = self._waiters
-        success = self._acquire_nowait()
-        rescheduled = False
-
-        if not success:
-            waiters.append(event := AsyncEvent())
-
-            try:
-                success = self._acquire_nowait()
-
-                if not success:
-                    success = await event
-                    rescheduled = True
-            finally:
-                if success or event.cancel():
-                    try:
-                        waiters.remove(event)
-                    except ValueError:
-                        pass
-                else:
-                    self.release()
-
-        if not rescheduled:
-            await asyncio.sleep(0)
-
-        return success
-
-    def sync_acquire(
-        self, /, *, blocking: bool = True, timeout: float | None = None
-    ) -> bool:
-        waiters = self._waiters
-        success = self._acquire_nowait()
-
-        if success := self._acquire_nowait():
-            return True
-
-        if not blocking:
-            return False
-
-        waiters.append(event := ThreadingEvent())
-
-        try:
-            success = self._acquire_nowait()
-
-            if not success:
-                success = event.wait(timeout)
-        finally:
-            if success or event.cancel():
-                try:
-                    waiters.remove(event)
-                except ValueError:
-                    pass
-            else:
-                self.release()
-
-        return success
-
-    def release(self) -> None:
-        waiters = self._waiters
-        unlocked = self._unlocked
-        count = 1
-
-        while True:
-            if waiters:
-                if not count:
-                    if self._acquire_nowait():
-                        count = 1
-                    else:
-                        break
-
-                try:
-                    event = waiters[0]
-                except IndexError:
-                    pass
-                else:
-                    if event.is_set():
-                        count -= 1
-
-                    try:
-                        waiters.remove(event)
-                    except ValueError:
-                        pass
-
-                    if count or unlocked:
-                        continue
-                    break
-
-            if count == 1:
-                unlocked.append(None)
-            elif count > 1:
-                unlocked.extend([None] * count)
-            else:
-                break
-
-            if waiters:
-                count = 0
-            else:
-                break
-
-    @property
-    def waiting(self, /) -> int:
-        return len(self._waiters)
-
-    @property
-    def value(self, /) -> int:
-        return len(self._unlocked)
-
-
 class _BaseQueue[T]:
     __slots__ = (
         "__get_waiters",
diff --git a/src/async_utils/dual_color.py b/src/async_utils/dual_color.py
index 7327ec3..340579f 100644
--- a/src/async_utils/dual_color.py
+++ b/src/async_utils/dual_color.py
@@ -14,6 +14,6 @@
 
 from __future__ import annotations
 
-from ._qs import LIFOQueue, PriorityQueue, Queue, QueueEmpty, QueueFull, Semaphore
+from ._qs import LIFOQueue, PriorityQueue, Queue, QueueEmpty, QueueFull
 
-__all__ = ("LIFOQueue", "PriorityQueue", "Queue", "QueueEmpty", "QueueFull", "Semaphore")
+__all__ = ("LIFOQueue", "PriorityQueue", "Queue", "QueueEmpty", "QueueFull")