diff --git a/src/nexgen/beamlines/I19_2_nxs.py b/src/nexgen/beamlines/I19_2_nxs.py
index 64bcc612..f8e7f530 100644
--- a/src/nexgen/beamlines/I19_2_nxs.py
+++ b/src/nexgen/beamlines/I19_2_nxs.py
@@ -11,10 +11,10 @@
 from typing import Any, NamedTuple, Optional
 
 import h5py
-import numpy as np
 from numpy.typing import ArrayLike
 from pydantic import field_validator
 
+from nexgen.tools.vds_tools import define_vds_dtype_from_bit_depth
 from nexgen.utils import get_iso_timestamp
 
 from .. import log
@@ -230,6 +230,7 @@ def eiger_writer(
     vds_offset: int = 0,
     notes: dict[str, Any] | None = None,
     data_entry_key: str = "data",
+    bit_depth: int = 32,
 ):
     """
     A function to call the NXmx nexus file writer for Eiger 2X 4M detector.
@@ -251,6 +252,8 @@ def eiger_writer(
             dataset name and value its data. Defaults to None.
         data_entry_key (str, optional): Dataset entry key in datafiles. eg. for gating mode it's data1.\
             Defaults to data.
+        bit_depth(int, optional): Default bit depth for eiger collections, used to define dtype of vds data. \
+            Defaults to 32.
 
     Raises:
         ValueError: If use_meta is set to False but axes_pos and det_pos haven't been passed.
@@ -338,7 +341,7 @@ def eiger_writer(
         logger.info(
             "Not using meta file to update metadata, only the external links will be set up."
         )
-        vds_dtype = np.uint32
+        vds_dtype = define_vds_dtype_from_bit_depth(bit_depth)
         # Update axes
         # Goniometer
         for gax in TR.axes_pos:
@@ -457,6 +460,7 @@ def serial_nexus_writer(
     use_meta: bool = False,
     vds_offset: int = 0,
     n_frames: int | None = None,
+    bit_depth: int = 32,
     notes: dict[str, Any] | None = None,
 ):
     """Wrapper function to gather all parameters from the beamline and kick off the nexus writer for a \
@@ -473,6 +477,8 @@ def serial_nexus_writer(
         n_frames (int | None, optional): Number of images for the nexus file. Only needed if different \
             from the tot_num_images in the collection params. If passed, the VDS will only contain the \
             number of frames specified here. Defaults to None.
+        bit_depth(int, optional): Default bit depth for eiger collections, used to define dtype of vds data. \
+            Defaults to 32.
         notes (dict[str, Any] | None, optional): Any additional information to be written as NXnote, \
             passed as a dictionary of (key, value) pairs where key represents the dataset name and \
             value its data. Defaults to None.
@@ -511,7 +517,8 @@ def serial_nexus_writer(
                 use_meta,
                 n_frames,
                 vds_offset,
-                notes,
+                bit_depth=bit_depth,
+                notes=notes,
             )
         case DetectorName.TRISTAN:
             tristan_writer(master_file, collection_params, timestamps, notes)
@@ -523,6 +530,7 @@ def nexus_writer(
     timestamps: tuple[datetime, datetime] = (None, None),
     use_meta: bool = False,
     data_entry_key: str = "data",
+    bit_depth: int = 32,
 ):
     """Wrapper function to gather all parameters from the beamline and kick off the nexus writer for a \
     standard experiment on I19-2.
@@ -536,6 +544,8 @@ def nexus_writer(
             all parameters will need to be passed manually. Defaults to False.
         data_entry_key (str, optional): Dataset entry key in datafiles. eg. for gating mode it's data1.\
             Defaults to data.
+        bit_depth(int, optional): Default bit depth for eiger collections, used to define dtype of vds data. \
+            Defaults to 32.
     """
     collection_params = CollectionParams(**params)
     wdir = master_file.parent
@@ -603,6 +613,7 @@ def nexus_writer(
                 timestamps,
                 use_meta,
                 data_entry_key=data_entry_key,
+                bit_depth=bit_depth,
             )
         case DetectorName.TRISTAN:
             tristan_writer(
diff --git a/src/nexgen/beamlines/SSX_Eiger_nxs.py b/src/nexgen/beamlines/SSX_Eiger_nxs.py
index b6c71f09..0fd3d477 100644
--- a/src/nexgen/beamlines/SSX_Eiger_nxs.py
+++ b/src/nexgen/beamlines/SSX_Eiger_nxs.py
@@ -8,8 +8,7 @@
 from pathlib import Path
 from typing import Literal, get_args
 
-import numpy as np
-from numpy.typing import DTypeLike
+from nexgen.tools.vds_tools import define_vds_dtype_from_bit_depth
 
 from .. import log
 from ..nxs_utils import (
@@ -64,16 +63,6 @@ class SerialParams(GeneralParams):
     experiment_type: str
 
 
-def _define_vds_dtype_from_bit_depth(bit_depth: int) -> DTypeLike:
-    """Define dtype of VDS based on the passed bit depth."""
-    if bit_depth == 32:
-        return np.uint32
-    elif bit_depth == 8:
-        return np.uint8
-    else:
-        return np.uint16
-
-
 def _get_beamline_specific_params(beamline: str) -> tuple[BeamlineAxes, EigerDetector]:
     """Get beamline specific axes and eiger description.
 
@@ -295,7 +284,7 @@ def ssx_eiger_writer(
         bit_depth = 32
     else:
         bit_depth = ssx_params["bit_depth"]
-    vds_dtype = _define_vds_dtype_from_bit_depth(bit_depth)
+    vds_dtype = define_vds_dtype_from_bit_depth(bit_depth)
     logger.debug(f"VDS dtype will be {vds_dtype}")
 
     # Define Goniometer axes
diff --git a/src/nexgen/command_line/I19_2_cli.py b/src/nexgen/command_line/I19_2_cli.py
index 61d913c8..30f2e7be 100644
--- a/src/nexgen/command_line/I19_2_cli.py
+++ b/src/nexgen/command_line/I19_2_cli.py
@@ -135,6 +135,7 @@ def nexgen_writer(args):
             args.use_meta,
             args.vds_offset,
             args.n_frames,
+            bit_depth=args.bit_depth,
         )
     else:
         nexus_writer(
@@ -143,6 +144,7 @@ def nexgen_writer(args):
             (_start, _stop),
             args.use_meta,
             data_entry_key=args.data_key,
+            bit_depth=args.bit_depth,
         )
 
 
@@ -304,6 +306,13 @@ def nexgen_writer(args):
     default="data",
     help="Data entry key of dataset in raw .h5 file. Defaults to data.",
 )
+parser_nex.add_argument(
+    "-bits" "--bit-depth",
+    type=int,
+    choices=[8, 16, 32],
+    default=32,
+    help="Default bit depth for eiger collections, used to define dtype of vds data. Defaults to 32.",
+)
 parser_nex.set_defaults(func=nexgen_writer)
 
 
diff --git a/src/nexgen/command_line/nexus_generator.py b/src/nexgen/command_line/nexus_generator.py
index b307043e..c2ce24c5 100644
--- a/src/nexgen/command_line/nexus_generator.py
+++ b/src/nexgen/command_line/nexus_generator.py
@@ -28,6 +28,7 @@
 from nexgen.nxs_write.nxmx_writer import EventNXmxFileWriter, NXmxFileWriter
 from nexgen.nxs_write.write_utils import find_number_of_images
 from nexgen.tools.data_writer import generate_event_files, generate_image_files
+from nexgen.tools.vds_tools import define_vds_dtype_from_bit_depth
 from nexgen.utils import (
     get_filename_template,
     get_iso_timestamp,
@@ -143,6 +144,7 @@ def write_nxmx_cli(args):
 
     try:
         entry_key = args.data_key if args.data_key else "data"
+        vds_dtype = define_vds_dtype_from_bit_depth(args.bit_depth)
         # Aaaaaaaaaaaand write
         if params.det.mode == "images":
             writer = NXmxFileWriter(
@@ -156,7 +158,7 @@ def write_nxmx_cli(args):
             )
             writer.write(image_datafiles=datafiles, data_entry_key=entry_key)
             if not args.no_vds:
-                writer.write_vds(args.vds_offset)
+                writer.write_vds(args.vds_offset, vds_dtype=vds_dtype)
         else:
             writer = EventNXmxFileWriter(
                 master_file,
@@ -390,6 +392,13 @@ def _parse_cli() -> argparse.ArgumentParser:
         default="data",
         help="Data entry key of dataset in raw .h5 file. Defaults to data.",
     )
+    nxmx_parser.add_argument(
+        "-bits" "--bit-depth",
+        type=int,
+        choices=[8, 16, 32],
+        default=32,
+        help="Default bit depth for eiger collections, used to define dtype of vds data. Defaults to 32.",
+    )
     nxmx_parser.set_defaults(func=write_nxmx_cli)
     demo_parser = subparsers.add_parser(
         "2",
diff --git a/src/nexgen/tools/vds_tools.py b/src/nexgen/tools/vds_tools.py
index a519bd65..1d4c82a6 100644
--- a/src/nexgen/tools/vds_tools.py
+++ b/src/nexgen/tools/vds_tools.py
@@ -21,6 +21,16 @@
 vds_logger = logging.getLogger("nexgen.VDSWriter")
 
 
+def define_vds_dtype_from_bit_depth(bit_depth: int) -> DTypeLike:
+    """Define dtype of VDS based on the passed bit depth."""
+    if bit_depth == 32:
+        return np.uint32
+    elif bit_depth == 8:
+        return np.uint8
+    else:
+        return np.uint16
+
+
 @dataclass
 class Dataset:
     name: str
diff --git a/tests/beamlines/test_i19nxs.py b/tests/beamlines/test_i19nxs.py
index 8d23520f..7ffd9e33 100644
--- a/tests/beamlines/test_i19nxs.py
+++ b/tests/beamlines/test_i19nxs.py
@@ -84,7 +84,8 @@ def test_serial_nexus_writer_calls_correct_writer_for_eiger(
         True,
         None,
         0,
-        None,
+        bit_depth=32,
+        notes=None,
     )
 
 
diff --git a/tests/tools/test_VDS_tools.py b/tests/tools/test_VDS_tools.py
index 92013f9e..5bf94bdf 100644
--- a/tests/tools/test_VDS_tools.py
+++ b/tests/tools/test_VDS_tools.py
@@ -8,6 +8,7 @@
 from nexgen.tools.vds_tools import (
     Dataset,
     create_virtual_layout,
+    define_vds_dtype_from_bit_depth,
     find_datasets_in_file,
     image_vds_writer,
     jungfrau_vds_writer,
@@ -15,6 +16,15 @@
 )
 
 
+@pytest.mark.parametrize(
+    "bit_depth, expected_dtype", [(8, np.uint8), (16, np.uint16), (32, np.uint32)]
+)
+def test_vds_dtype_from_input(bit_depth, expected_dtype):
+    d = define_vds_dtype_from_bit_depth(bit_depth)
+
+    assert d == expected_dtype
+
+
 def test_when_get_frames_and_shape_less_than_1000_then_correct():
     sshape = split_datasets(["test1"], (500, 10, 10))
     assert sshape == [Dataset("test1", (500, 10, 10), 0, 500)]