diff --git a/adafruit_wiznet5k/adafruit_wiznet5k_socket.py b/adafruit_wiznet5k/adafruit_wiznet5k_socket.py
index e0687a0..f250983 100644
--- a/adafruit_wiznet5k/adafruit_wiznet5k_socket.py
+++ b/adafruit_wiznet5k/adafruit_wiznet5k_socket.py
@@ -145,9 +145,13 @@ def inet_ntoa(ip_address: Union[bytes, bytearray]) -> str:
     return _the_interface.pretty_ip(ip_address)
 
 
-SOCK_STREAM = const(0x21)  # TCP
-_TCP_MODE = 80
-SOCK_DGRAM = const(0x02)  # UDP
+# These must match circuitpython "socketpoool" values. However, we cannot
+# depend on socketpool being importable, so hard-code them here.
+SOCK_STREAM = 1
+SOCK_DGRAM = 2
+
+_SOCKET_TYPE_TO_WIZNET = b"\0\x21\2"
+
 AF_INET = const(3)
 _SOCKET_INVALID = const(255)
 
@@ -431,7 +435,7 @@ def connect(self, address: Tuple[str, int]) -> None:
             self._socknum,
             _the_interface.unpretty_ip(gethostbyname(address[0])),
             address[1],
-            self._sock_type,
+            _SOCKET_TYPE_TO_WIZNET[self._sock_type],
         )
         _the_interface.src_port = 0
         if not result:
@@ -674,7 +678,9 @@ def _available(self) -> int:
 
         :return int: Number of bytes available.
         """
-        return _the_interface.socket_available(self._socknum, self._sock_type)
+        return _the_interface.socket_available(
+            self._socknum, _SOCKET_TYPE_TO_WIZNET[self._sock_type]
+        )
 
     @_check_socket_closed
     def settimeout(self, value: Optional[float]) -> None: