diff --git a/src/hangar/dataloaders/grouper.py b/src/hangar/dataloaders/grouper.py
index 0ba618ac..e6c16241 100644
--- a/src/hangar/dataloaders/grouper.py
+++ b/src/hangar/dataloaders/grouper.py
@@ -1,11 +1,10 @@
 import numpy as np
 
 from ..arrayset import ArraysetDataReader
+from ..records.hashmachine import array_hash_digest
 
 from collections import defaultdict
-import hashlib
-from typing import Sequence, Union, Iterable, NamedTuple
-import struct
+from typing import Sequence, Union, Iterable, NamedTuple, Tuple
 
 
 # -------------------------- typehints ---------------------------------------
@@ -21,13 +20,6 @@
 # ------------------------------------------------------------------------------
 
 
-def _calculate_hash_digest(data: np.ndarray) -> str:
-    hasher = hashlib.blake2b(data, digest_size=20)
-    hasher.update(struct.pack(f'<{len(data.shape)}QB', *data.shape, data.dtype.num))
-    digest = hasher.hexdigest()
-    return digest
-
-
 class FakeNumpyKeyDict(object):
     def __init__(self, group_spec_samples, group_spec_value, group_digest_spec):
         self._group_spec_samples = group_spec_samples
@@ -35,7 +27,7 @@ def __init__(self, group_spec_samples, group_spec_value, group_digest_spec):
         self._group_digest_spec = group_digest_spec
 
     def __getitem__(self, key: np.ndarray) -> ArraysetSampleNames:
-        digest = _calculate_hash_digest(key)
+        digest = array_hash_digest(key)
         spec = self._group_digest_spec[digest]
         samples = self._group_spec_samples[spec]
         return samples
@@ -53,7 +45,7 @@ def __len__(self) -> int:
         return len(self._group_digest_spec)
 
     def __contains__(self, key: np.ndarray) -> bool:
-        digest = _calculate_hash_digest(key)
+        digest = array_hash_digest(key)
         res = True if digest in self._group_digest_spec else False
         return res
 
@@ -69,7 +61,7 @@ def values(self) -> Iterable[ArraysetSampleNames]:
         for spec in self._group_digest_spec.values():
             yield self._group_spec_samples[spec]
 
-    def items(self) -> Iterable[ArraysetSampleNames]:
+    def items(self) -> Iterable[Tuple[np.ndarray, ArraysetSampleNames]]:
         for spec in self._group_digest_spec.values():
             yield (self._group_spec_value[spec], self._group_spec_samples[spec])
 
@@ -81,11 +73,10 @@ def __repr__(self):
     def _repr_pretty_(self, p, cycle):
         res = f'Mapping: Group Data Value -> Sample Name \n'
         for k, v in self.items():
-            res += f'\n {k} :: {v}'
+            res += f'\n {k} :: {v} \n'
         p.text(res)
 
 
-
 # ---------------------------- MAIN METHOD ------------------------------------
 
 
@@ -112,7 +103,7 @@ def _setup(self):
         for spec, names in self._group_spec_samples.items():
             data = self.__arrayset._fs[spec.backend].read_data(spec)
             self._group_spec_value[spec] = data
-            digest = _calculate_hash_digest(data)
+            digest = array_hash_digest(data)
             self._group_digest_spec[digest] = spec
 
     @property