diff --git a/fixtracks/widgets/classifier.py b/fixtracks/widgets/classifier.py
index 998dfcb..506cd42 100644
--- a/fixtracks/widgets/classifier.py
+++ b/fixtracks/widgets/classifier.py
@@ -1,23 +1,30 @@
 import logging
 import numpy as np
 
-from PySide6.QtWidgets import QWidget, QVBoxLayout, QSizePolicy, QGraphicsView, QSlider, QPushButton, QLabel
-from PySide6.QtWidgets import QGraphicsScene, QGraphicsEllipseItem, QGraphicsRectItem, QGraphicsLineItem
-from PySide6.QtCore import Qt
-from PySide6.QtGui import QBrush, QColor, QPen, QPainter, QFont
+from PySide6.QtWidgets import QWidget, QVBoxLayout, QTabWidget,QPushButton
+from PySide6.QtCore import Signal
+from PySide6.QtGui import QBrush, QColor
 
 import pyqtgraph as pg
 
-from IPython import embed
 
 class SizeClassifier(QWidget):
+    apply = Signal()
+
     def __init__(self, parent=None):
         super().__init__(parent)
         self._t1_selection = None
         self._t2_selection = None
-        layout = QVBoxLayout()
+        self._coordinates = None
+        self._sizes = None
+
         self._plot_widget = self.setupGraph()
+        self._apply_btn = QPushButton("apply")
+        self._apply_btn.clicked.connect(lambda: self.apply.emit())
+
+        layout = QVBoxLayout()
         layout.addWidget(self._plot_widget)
+        layout.addWidget(self._apply_btn)
         self.setLayout(layout)
 
     def setupGraph(self):
@@ -51,8 +58,9 @@ class SizeClassifier(QWidget):
         return hist, edges
 
     def setCoordinates(self, coordinates):
-        dists = self.estimate_length(coordinates)
-        n, e = self.estimate_histogram(dists)
+        self._coordinates = coordinates
+        self._sizes = self.estimate_length(coordinates)
+        n, e = self.estimate_histogram(self._sizes)
         plot = self._plot_widget.addPlot()
         bgi = pg.BarGraphItem(x0=e[:-1], x1=e[1:], height=n, pen='w', brush=(0,0,255,150))
         plot.addItem(bgi)
@@ -67,6 +75,32 @@ class SizeClassifier(QWidget):
         else:
             return self._t2_selection.getRegion()
 
+    def assignedTracks(self):
+        tracks = np.ones_like(self._sizes, dtype=int) * -1
+        t1lower, t1upper = self.selections()
+        t2lower, t2upper = self.selections(False)
+        tracks[(self._sizes >= t1lower) & (self._sizes < t1upper)] = 1
+        tracks[(self._sizes >= t2lower) & (self._sizes < t2upper)] = 2
+        return tracks
+
+
+class ClassifierWidget(QTabWidget):
+    apply_sizeclassifier = Signal(np.ndarray)
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._size_classifier = SizeClassifier()
+        self.addTab(self._size_classifier, "Size classifier")
+        self._size_classifier.apply.connect(self._on_applySizeClassifier)
+
+    def _on_applySizeClassifier(self):
+        tracks = self.size_classifier.assignedTracks()
+        self.apply_sizeclassifier.emit(tracks)
+
+    @property
+    def size_classifier(self):
+        return self._size_classifier
+
 
 def main():
     import pickle
@@ -78,7 +112,6 @@ def main():
     with open(datafile, "rb") as f:
         df = pickle.load(f)
 
-
     coords = np.stack(df.keypoints.values,).astype(np.float32)[:,:,:]
 
     app = QApplication([])
@@ -98,4 +131,4 @@ def main():
     app.exec()
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()