diff --git a/a2s/a2s_async.py b/a2s/a2s_async.py
index 29718c3..9037fb4 100644
--- a/a2s/a2s_async.py
+++ b/a2s/a2s_async.py
@@ -148,6 +148,14 @@ async def request_async_impl(
 
 
 class A2SProtocol(asyncio.DatagramProtocol):
+    __slots__ = (
+        "recv_queue",
+        "error_event",
+        "error",
+        "fragment_buf",
+        "transport",
+    )
+
     def __init__(self):
         self.recv_queue: asyncio.Queue[bytes] = asyncio.Queue()
         self.error_event: asyncio.Event = asyncio.Event()
@@ -192,6 +200,12 @@ class A2SProtocol(asyncio.DatagramProtocol):
 
 
 class A2SStreamAsync:
+    __slots__ = (
+        "transport",
+        "protocol",
+        "timeout",
+    )
+
     def __init__(self, transport: asyncio.DatagramTransport, protocol: A2SProtocol, timeout: float) -> None:
         self.transport = transport
         self.protocol = protocol
diff --git a/a2s/a2s_fragment.py b/a2s/a2s_fragment.py
index 8c7497d..de54b96 100644
--- a/a2s/a2s_fragment.py
+++ b/a2s/a2s_fragment.py
@@ -29,6 +29,16 @@ from a2s.byteio import ByteReader
 
 
 class A2SFragment:
+    __slots__ = (
+        "message_id",
+        "fragment_count",
+        "fragment_id",
+        "mtu",
+        "decompressed_size",
+        "crc",
+        "payload",
+    )
+
     def __init__(
         self,
         message_id: int,
diff --git a/a2s/a2s_sync.py b/a2s/a2s_sync.py
index b26ace8..5a93c00 100644
--- a/a2s/a2s_sync.py
+++ b/a2s/a2s_sync.py
@@ -48,8 +48,6 @@ logger: logging.Logger = logging.getLogger("a2s")
 
 T = TypeVar("T", InfoProtocol, RulesProtocol, PlayersProtocol)
 
-__all__ = ("A2SStream",)
-
 
 @overload
 def request_sync(
@@ -139,6 +137,11 @@ def request_sync_impl(
 
 
 class A2SStream:
+    __slots__ = (
+        "address",
+        "_socket",
+    )
+
     def __init__(self, address: Tuple[str, int], timeout: float) -> None:
         self.address: Tuple[str, int] = address
         self._socket: socket.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
diff --git a/a2s/byteio.py b/a2s/byteio.py
index 2bbe734..3eaea6e 100644
--- a/a2s/byteio.py
+++ b/a2s/byteio.py
@@ -32,7 +32,6 @@ from a2s.exceptions import BufferExhaustedError
 
 from .defaults import DEFAULT_ENCODING
 
-
 if TYPE_CHECKING:
     from typing_extensions import Literal
 
@@ -42,6 +41,12 @@ STRUCT_OPTIONS = Literal[
 
 
 class ByteReader:
+    __slots__ = (
+        "stream",
+        "endian",
+        "encoding",
+    )
+
     def __init__(self, stream: io.BytesIO, endian: str = "=", encoding: Optional[str] = None) -> None:
         self.stream: io.BytesIO = stream
         self.endian: str = endian
@@ -126,6 +131,12 @@ class ByteReader:
 
 
 class ByteWriter:
+    __slots__ = (
+        "stream",
+        "endian",
+        "encoding",
+    )
+
     def __init__(self, stream: io.BytesIO, endian: str = "=", encoding: Optional[str] = None) -> None:
         self.stream: io.BytesIO = stream
         self.endian: str = endian