diff --git a/piker/data/_sharedmem.py b/piker/data/_sharedmem.py
index 1172fc7b..82f61e79 100644
--- a/piker/data/_sharedmem.py
+++ b/piker/data/_sharedmem.py
@@ -27,13 +27,14 @@ from multiprocessing.shared_memory import SharedMemory, _USE_POSIX
 if _USE_POSIX:
     from _posixshmem import shm_unlink
 
-import tractor
+# import msgspec
 import numpy as np
-from pydantic import BaseModel
 from numpy.lib import recfunctions as rfn
+import tractor
 
 from ..log import get_logger
 from ._source import base_iohlc_dtype
+from .types import Struct
 
 
 log = get_logger(__name__)
@@ -107,15 +108,12 @@ class SharedInt:
                 log.warning(f'Shm for {name} already unlinked?')
 
 
-class _Token(BaseModel):
+class _Token(Struct, frozen=True):
     '''
     Internal represenation of a shared memory "token"
     which can be used to key a system wide post shm entry.
 
     '''
-    class Config:
-        frozen = True
-
     shm_name: str  # this servers as a "key" value
     shm_first_index_name: str
     shm_last_index_name: str
@@ -126,17 +124,22 @@ class _Token(BaseModel):
         return np.dtype(list(map(tuple, self.dtype_descr))).descr
 
     def as_msg(self):
-        return self.dict()
+        return self.to_dict()
 
     @classmethod
     def from_msg(cls, msg: dict) -> _Token:
         if isinstance(msg, _Token):
             return msg
 
+        # TODO: native struct decoding
+        # return _token_dec.decode(msg)
+
         msg['dtype_descr'] = tuple(map(tuple, msg['dtype_descr']))
         return _Token(**msg)
 
 
+# _token_dec = msgspec.msgpack.Decoder(_Token)
+
 # TODO: this api?
 # _known_tokens = tractor.ActorVar('_shm_tokens', {})
 # _known_tokens = tractor.ContextStack('_known_tokens', )
@@ -167,7 +170,7 @@ def _make_token(
         shm_name=key,
         shm_first_index_name=key + "_first",
         shm_last_index_name=key + "_last",
-        dtype_descr=np.dtype(dtype).descr
+        dtype_descr=tuple(np.dtype(dtype).descr)
     )