diff --git a/src/main/java/ai/nets/samj/gui/MainGUI.java b/src/main/java/ai/nets/samj/gui/MainGUI.java
index 637fa80..c12eaf0 100644
--- a/src/main/java/ai/nets/samj/gui/MainGUI.java
+++ b/src/main/java/ai/nets/samj/gui/MainGUI.java
@@ -547,8 +547,14 @@ public void modelActionsOnImageChanged() {
             public void imageActionsOnImageChanged() {
                 consumer.deactivateListeners();
                 consumer.deselectImage();
-                setTwoThirdsEnabled(false);
-                go.setEnabled(cmbImages.getSelectedObject() != null);
+            	setTwoThirdsEnabled(false);
+                if (go.isEnabled())
+                	return;
+                go.showAnimation(true);
+                new Thread(() -> {
+                    go.setEnabled(cmbModels.getSelectedModel().isInstalled());
+                    go.showAnimation(false);
+                }).start();
             }
         };
         modelListener = new ModelSelectionListener() {
@@ -564,6 +570,12 @@ public void changeDrawerPanel() {
 			public void changeGUI() {
                 setTwoThirdsEnabled(false);
                 go.setEnabled(cmbImages.getSelectedObject() != null);
+                go.setEnabled(false);
+                go.showAnimation(true);
+                new Thread(() -> {
+                    go.setEnabled(cmbModels.getSelectedModel().isInstalled());
+                    go.showAnimation(false);
+                }).start();
 			}
         };
         modelDrawerListener = new ModelDrawerPanelListener() {
diff --git a/src/main/java/ai/nets/samj/install/Sam2EnvManager.java b/src/main/java/ai/nets/samj/install/Sam2EnvManager.java
index 526f1b8..1679a2a 100644
--- a/src/main/java/ai/nets/samj/install/Sam2EnvManager.java
+++ b/src/main/java/ai/nets/samj/install/Sam2EnvManager.java
@@ -57,18 +57,6 @@ public class Sam2EnvManager extends SamEnvManagerAbstract {
 	 * Default version for the family of SAM2 models
 	 */
 	final public static String DEFAULT_SAM2 = "tiny";
-	/**
-	 * Name of the file that contains the weights of SAM Huge
-	 */
-	final public static String SAM2_TINY_WEIGHTS_NAME = "sam2_hiera_tiny.pth";
-	/**
-	 * Name of the file that contains the weights of SAM Huge
-	 */
-	final public static String SAM2_SMALL_WEIGHTS_NAME = "sam2_hiera_small.pth";
-	/**
-	 * Name of the file that contains the weights of SAM Huge
-	 */
-	final public static String SAM2_LARGE_WEIGHTS_NAME = "sam2_hiera_large.pth";
 
 	/**
 	 * Dependencies to be checked to make sure that the environment is able to load a SAM based model. 
@@ -99,7 +87,7 @@ else if (!PlatformDetection.getArch().equals(PlatformDetection.ARCH_ARM64) && !P
 			INSTALL_PIP_DEPS = Arrays.asList(new String[] {"samv2==0.0.4", "pytest"});
 	}
 	/**
-	 * Byte sizes of all the EfficientViTSAM options
+	 * Byte sizes of all the SAM2 options
 	 */
 	final public static HashMap<String, Long> SAM2_BYTE_SIZES_MAP;
 	static {
@@ -109,6 +97,17 @@ else if (!PlatformDetection.getArch().equals(PlatformDetection.ARCH_ARM64) && !P
 		SAM2_BYTE_SIZES_MAP.put("base_plus", (long) -1);
 		SAM2_BYTE_SIZES_MAP.put("large", (long) 897952466);
 	}
+	/**
+	 * Byte sizes of all the SAM2.1 options
+	 */
+	final public static HashMap<String, Long> SAM2_1_BYTE_SIZES_MAP;
+	static {
+		SAM2_1_BYTE_SIZES_MAP = new HashMap<String, Long>();
+		SAM2_1_BYTE_SIZES_MAP.put("tiny", (long) 156_008_466);
+		SAM2_1_BYTE_SIZES_MAP.put("small", (long) 184_416_285);
+		SAM2_1_BYTE_SIZES_MAP.put("base_plus", (long) 323_606_802);
+		SAM2_1_BYTE_SIZES_MAP.put("large", (long) 898_083_611);
+	}
 	/**
 	 * Name of the environment that contains the code and weigths to run EfficientSAM models
 	 */
@@ -118,9 +117,13 @@ else if (!PlatformDetection.getArch().equals(PlatformDetection.ARCH_ARM64) && !P
 	 */
 	final static public String SAM2_NAME = "sam2";
 	/**
-	 * URL to download the EfficientSAM model 
+	 * URL to download the SAM2 model 
+	 */
+	final static private String SAM2_URL = "https://dl.fbaipublicfiles.com/segment_anything_2/092824/sam2.1_hiera_%s.pt";
+	/**
+	 * URL to download the SAM2 model 
 	 */
-	final static public String SAM2_URL = "https://dl.fbaipublicfiles.com/segment_anything_2/092824/sam2.1_hiera_%s.pt";
+	final static private String SAM2_FNAME = "sam2.1_hiera_%s.pt";
 	
 	private Sam2EnvManager(String modelType) {
 		List<String> modelTypes = SAM2_BYTE_SIZES_MAP.keySet().stream().collect(Collectors.toList());
@@ -381,7 +384,11 @@ public String getModelEnv() {
 	 * @return the official name of the EfficientSAM Small weights
 	 */
 	public String getModelWeigthsName() {
-		return "sam2_hiera_" + modelType + ".pt";
+		try {
+			return DownloadModel.getFileNameFromURLString(String.format(SAM2_URL, modelType));
+		} catch (MalformedURLException e) {
+			return String.format(SAM2_FNAME, modelType);
+		}
 	}
 
 	@Override
@@ -390,7 +397,7 @@ public String getModelWeigthPath() {
 		try {
 			file = Paths.get(path, "envs", SAM2_ENV_NAME, SAM2_NAME, "weights", DownloadModel.getFileNameFromURLString(String.format(SAM2_URL, modelType))).toFile();
 		} catch (MalformedURLException e) {
-			file = Paths.get(path, "envs", SAM2_ENV_NAME, SAM2_NAME, "weights", String.format("sam2_hiera_%s.pt", modelType)).toFile();
+			file = Paths.get(path, "envs", SAM2_ENV_NAME, SAM2_NAME, "weights", String.format(SAM2_FNAME, modelType)).toFile();
 		}
 
 		return file.getAbsolutePath();