diff --git a/hubconf.py b/hubconf.py
index a65f866c..c85acf43 100644
--- a/hubconf.py
+++ b/hubconf.py
@@ -1,5 +1,5 @@
 # Optional list of dependencies required by the package
 dependencies = ['yaml', 'torch', 'torchvision']
 
-from models import yolov5s as yolov5
+from models import yolov5
 from models import yolov5_onnx
diff --git a/models/__init__.py b/models/__init__.py
index a9769ad3..2c1ff2ec 100644
--- a/models/__init__.py
+++ b/models/__init__.py
@@ -1,20 +1,21 @@
 from torch import nn
 
 from .common import Conv
-from .yolo import yolov5s
+from .yolo import yolov5
 
 from utils.activations import Hardswish
 
 
 def yolov5_onnx(
+    cfg_path='yolov5s.yaml',
     pretrained=False,
     progress=True,
     num_classes=80,
     **kwargs,
 ):
 
-    model = yolov5s(pretrained=pretrained, progress=progress,
-                    num_classes=num_classes, **kwargs)
+    model = yolov5(cfg_path=cfg_path, pretrained=pretrained, progress=progress,
+                   num_classes=num_classes, **kwargs)
     for m in model.modules():
         m._non_persistent_buffers_set = set()  # pytorch 1.6.0 compatibility
         if isinstance(m, Conv) and isinstance(m.act, nn.Hardswish):
diff --git a/models/backbone.py b/models/backbone.py
index e0e30a8c..d3ab848c 100644
--- a/models/backbone.py
+++ b/models/backbone.py
@@ -1,5 +1,5 @@
 # Modified from ultralytics/yolov5 by Zhiqiang Wang
-import pathlib
+from pathlib import Path
 from collections import OrderedDict
 
 import yaml
@@ -189,7 +189,7 @@ def forward(self, x):
 
 
 def darknet(cfg_path='yolov5s.yaml', pretrained=False):
-    cfg_path = pathlib.Path(__file__).parent.absolute().joinpath(cfg_path)
+    cfg_path = Path(__file__).parent.absolute().joinpath(cfg_path)
     with open(cfg_path) as f:
         model_dict = yaml.load(f, Loader=yaml.FullLoader)
 
diff --git a/models/yolo.py b/models/yolo.py
index f96927b2..dbde5db0 100644
--- a/models/yolo.py
+++ b/models/yolo.py
@@ -1,6 +1,7 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
 # Modified by Zhiqiang Wang (zhiqwang@outlook.com)
 import warnings
+from pathlib import Path
 
 import torch
 from torch import nn, Tensor
@@ -151,13 +152,14 @@ def forward(
 
 
 model_urls = {
-    'yolov5s':
-        'https://github.com/zhiqwang/yolov5-rt-stack/releases/download/v0.2.1/yolov5s.pt',
+    'yolov5s': 'https://github.com/zhiqwang/yolov5-rt-stack/releases/download/v0.2.1/yolov5s.pt',
+    'yolov5m': 'https://github.com/zhiqwang/yolov5-rt-stack/releases/download/v0.2.4/yolov5m.pt',
+    'yolov5l': 'https://github.com/zhiqwang/yolov5-rt-stack/releases/download/v0.2.4/yolov5l.pt',
 }
 
 
-def yolov5s(pretrained=False, progress=True,
-            num_classes=80, pretrained_backbone=True, **kwargs):
+def yolov5(cfg_path='yolov5s.yaml', pretrained=False, progress=True,
+           num_classes=80, pretrained_backbone=True, **kwargs):
     """
     Constructs a YOLO model.
 
@@ -185,7 +187,7 @@ def yolov5s(pretrained=False, progress=True,
 
     Example::
 
-        >>> model = yolov5s(pretrained=True)
+        >>> model = yolov5(pretrained=True)
         >>> model.eval()
         >>> x = [torch.rand(3, 416, 320), torch.rand(3, 480, 352)]
         >>> predictions = model(x)
@@ -198,9 +200,9 @@ def yolov5s(pretrained=False, progress=True,
         # no need to download the backbone if pretrained is set
         pretrained_backbone = False
     # skip P2 because it generates too many anchors (according to their paper)
-    backbone, anchor_grids = darknet(cfg_path='yolov5s.yaml', pretrained=pretrained_backbone)
+    backbone, anchor_grids = darknet(cfg_path=cfg_path, pretrained=pretrained_backbone)
     model = YOLO(backbone, num_classes, anchor_grids, **kwargs)
     if pretrained:
-        state_dict = load_state_dict_from_url(model_urls['yolov5s'], progress=progress)
+        state_dict = load_state_dict_from_url(model_urls[Path(cfg_path).stem], progress=progress)
         model.load_state_dict(state_dict)
     return model
diff --git a/models/yolov5l.yaml b/models/yolov5l.yaml
new file mode 100644
index 00000000..13095541
--- /dev/null
+++ b/models/yolov5l.yaml
@@ -0,0 +1,48 @@
+# parameters
+nc: 80  # number of classes
+depth_multiple: 1.0  # model depth multiple
+width_multiple: 1.0  # layer channel multiple
+
+# anchors
+anchors:
+  - [10,13, 16,30, 33,23]  # P3/8
+  - [30,61, 62,45, 59,119]  # P4/16
+  - [116,90, 156,198, 373,326]  # P5/32
+
+# YOLOv5 backbone
+backbone:
+  # [from, number, module, args]
+  [[-1, 1, Focus, [64, 3]],  # 0-P1/2
+   [-1, 1, Conv, [128, 3, 2]],  # 1-P2/4
+   [-1, 3, BottleneckCSP, [128]],
+   [-1, 1, Conv, [256, 3, 2]],  # 3-P3/8
+   [-1, 9, BottleneckCSP, [256]],
+   [-1, 1, Conv, [512, 3, 2]],  # 5-P4/16
+   [-1, 9, BottleneckCSP, [512]],
+   [-1, 1, Conv, [1024, 3, 2]],  # 7-P5/32
+   [-1, 1, SPP, [1024, [5, 9, 13]]],
+   [-1, 3, BottleneckCSP, [1024, False]],  # 9
+  ]
+
+# YOLOv5 head
+head:
+  [[-1, 1, Conv, [512, 1, 1]],
+   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
+   [[-1, 6], 1, Concat, [1]],  # cat backbone P4
+   [-1, 3, BottleneckCSP, [512, False]],  # 13
+
+   [-1, 1, Conv, [256, 1, 1]],
+   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
+   [[-1, 4], 1, Concat, [1]],  # cat backbone P3
+   [-1, 3, BottleneckCSP, [256, False]],  # 17 (P3/8-small)
+
+   [-1, 1, Conv, [256, 3, 2]],
+   [[-1, 14], 1, Concat, [1]],  # cat head P4
+   [-1, 3, BottleneckCSP, [512, False]],  # 20 (P4/16-medium)
+
+   [-1, 1, Conv, [512, 3, 2]],
+   [[-1, 10], 1, Concat, [1]],  # cat head P5
+   [-1, 3, BottleneckCSP, [1024, False]],  # 23 (P5/32-large)
+
+   [[17, 20, 23], 1, Detect, [nc, anchors]],  # Detect(P3, P4, P5)
+  ]
diff --git a/models/yolov5m.yaml b/models/yolov5m.yaml
new file mode 100644
index 00000000..eb50a713
--- /dev/null
+++ b/models/yolov5m.yaml
@@ -0,0 +1,48 @@
+# parameters
+nc: 80  # number of classes
+depth_multiple: 0.67  # model depth multiple
+width_multiple: 0.75  # layer channel multiple
+
+# anchors
+anchors:
+  - [10,13, 16,30, 33,23]  # P3/8
+  - [30,61, 62,45, 59,119]  # P4/16
+  - [116,90, 156,198, 373,326]  # P5/32
+
+# YOLOv5 backbone
+backbone:
+  # [from, number, module, args]
+  [[-1, 1, Focus, [64, 3]],  # 0-P1/2
+   [-1, 1, Conv, [128, 3, 2]],  # 1-P2/4
+   [-1, 3, BottleneckCSP, [128]],
+   [-1, 1, Conv, [256, 3, 2]],  # 3-P3/8
+   [-1, 9, BottleneckCSP, [256]],
+   [-1, 1, Conv, [512, 3, 2]],  # 5-P4/16
+   [-1, 9, BottleneckCSP, [512]],
+   [-1, 1, Conv, [1024, 3, 2]],  # 7-P5/32
+   [-1, 1, SPP, [1024, [5, 9, 13]]],
+   [-1, 3, BottleneckCSP, [1024, False]],  # 9
+  ]
+
+# YOLOv5 head
+head:
+  [[-1, 1, Conv, [512, 1, 1]],
+   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
+   [[-1, 6], 1, Concat, [1]],  # cat backbone P4
+   [-1, 3, BottleneckCSP, [512, False]],  # 13
+
+   [-1, 1, Conv, [256, 1, 1]],
+   [-1, 1, nn.Upsample, [None, 2, 'nearest']],
+   [[-1, 4], 1, Concat, [1]],  # cat backbone P3
+   [-1, 3, BottleneckCSP, [256, False]],  # 17 (P3/8-small)
+
+   [-1, 1, Conv, [256, 3, 2]],
+   [[-1, 14], 1, Concat, [1]],  # cat head P4
+   [-1, 3, BottleneckCSP, [512, False]],  # 20 (P4/16-medium)
+
+   [-1, 1, Conv, [512, 3, 2]],
+   [[-1, 10], 1, Concat, [1]],  # cat head P5
+   [-1, 3, BottleneckCSP, [1024, False]],  # 23 (P5/32-large)
+
+   [[17, 20, 23], 1, Detect, [nc, anchors]],  # Detect(P3, P4, P5)
+  ]
diff --git a/utils/updated_checkpoint.py b/utils/updated_checkpoint.py
index d336684c..5d24f028 100644
--- a/utils/updated_checkpoint.py
+++ b/utils/updated_checkpoint.py
@@ -6,7 +6,13 @@
 
 
 def update_ultralytics(model, checkpoint_path_ultralytics):
+    """
+    It's limited that ultralytics saved model must load in their root path.
+    So a very important thing is to desensitize the path befor updating ultralytics's trained model as follows:
 
+        >>> checkpoints_ = torch.load(weights, map_location='cpu')['model']
+        >>> torch.save(checkpoints_.state_dict(), './checkpoints/yolov5/yolov5s_ultralytics.pt')
+    """
     state_dict = torch.load(checkpoint_path_ultralytics, map_location="cpu")
 
     # Update body features