diff --git a/src/meta_memcache/connection/memcache_socket.py b/src/meta_memcache/connection/memcache_socket.py
index b396961..7bf14cf 100644
--- a/src/meta_memcache/connection/memcache_socket.py
+++ b/src/meta_memcache/connection/memcache_socket.py
@@ -21,6 +21,9 @@
 )
 
 _log: logging.Logger = logging.getLogger(__name__)
+NOT_STORED = NotStored()
+MISS = Miss()
+CONFLICT = Conflict()
 
 
 class MemcacheSocket:
@@ -224,15 +227,15 @@ def get_response(
                 self._add_flags(result, chunks)
             elif response_code == b"NS":
                 # Value response, parse size and flags
-                result = NotStored()
+                result = NOT_STORED
                 assert len(chunks) == 0  # noqa: S101
             elif response_code == b"EX":
                 # Already exists, not changed, CAS conflict
-                result = Conflict()
+                result = CONFLICT
                 assert len(chunks) == 0  # noqa: S101
             elif response_code == b"EN" or response_code == b"NF":
                 # Not Found, Miss.
-                result = Miss()
+                result = MISS
                 assert len(chunks) == 0  # noqa: S101
             else:
                 raise MemcacheError(f"Unknown response: {bytes(response_code)!r}")
diff --git a/src/meta_memcache/protocol.py b/src/meta_memcache/protocol.py
index 2bdf826..831c7a6 100644
--- a/src/meta_memcache/protocol.py
+++ b/src/meta_memcache/protocol.py
@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from enum import Enum, IntEnum
-from typing import Any, Dict, List, NamedTuple, Optional, Set, Union
+from typing import Any, Dict, List, Optional, Set, Union
 
 ENDL = b"\r\n"
 NOOP: bytes = b"mn" + ENDL
@@ -8,10 +8,25 @@
 SPACE: int = ord(" ")
 
 
-class Key(NamedTuple):
+@dataclass
+class Key:
+    __slots__ = ("key", "routing_key", "is_unicode")
     key: str
-    routing_key: Optional[str] = None
-    is_unicode: bool = False
+    routing_key: Optional[str]
+    is_unicode: bool
+
+    def __init__(
+        self,
+        key: str,
+        routing_key: Optional[str] = None,
+        is_unicode: bool = False,
+    ) -> None:
+        self.key = key
+        self.routing_key = routing_key
+        self.is_unicode = is_unicode
+
+    def __hash__(self) -> int:
+        return hash((self.key, self.routing_key))
 
 
 class MetaCommand(Enum):
@@ -84,16 +99,19 @@ class TokenFlag(Enum):
 token_flags_values: Dict[int, TokenFlag] = {f.value[0]: f for f in TokenFlag}
 
 
+@dataclass
 class MemcacheResponse:
-    pass
+    __slots__ = ()
 
 
+@dataclass
 class Miss(MemcacheResponse):
-    pass
+    __slots__ = ()
 
 
 @dataclass
 class Success(MemcacheResponse):
+    __slots__ = ("flags", "int_flags", "token_flags")
     flags: Set[Flag]
     int_flags: Dict[IntFlag, int]
     token_flags: Dict[TokenFlag, bytes]
@@ -111,6 +129,7 @@ def __init__(
 
 @dataclass
 class Value(Success):
+    __slots__ = ("flags", "int_flags", "token_flags", "size", "value")
     size: int
     value: Optional[Any]
 
@@ -127,7 +146,9 @@ def __init__(
         self.value = value
 
 
-class ValueContainer(NamedTuple):
+@dataclass
+class ValueContainer:
+    __slots__ = ("value",)
     value: Any
 
 
@@ -137,12 +158,12 @@ class ValueContainer(NamedTuple):
 
 @dataclass
 class NotStored(MemcacheResponse):
-    pass
+    __slots__ = ()
 
 
 @dataclass
 class Conflict(MemcacheResponse):
-    pass
+    __slots__ = ()
 
 
 ReadResponse = Union[Miss, Value, Success]