diff --git a/src/autorouter/autorouter.rs b/src/autorouter/autorouter.rs
index 7a447ad..73f4d65 100644
--- a/src/autorouter/autorouter.rs
+++ b/src/autorouter/autorouter.rs
@@ -12,7 +12,10 @@ use petgraph::{
 use spade::InsertionError;
 
 use crate::{
-    autorouter::ratsnest::{Ratsnest, RatsnestVertexIndex},
+    autorouter::{
+        ratsnest::{Ratsnest, RatsnestVertexIndex},
+        selection::Selection,
+    },
     drawing::{
         dot::FixedDotIndex,
         graph::{GetLayer, GetMaybeNet},
@@ -122,11 +125,7 @@ impl<R: RulesTrait> Autorouter<R> {
         Ok(Self { layout, ratsnest })
     }
 
-    pub fn autoroute(
-        &mut self,
-        selection: &HashSet<NodeIndex>,
-        observer: &mut impl RouterObserverTrait<R>,
-    ) {
+    pub fn autoroute(&mut self, selection: &Selection, observer: &mut impl RouterObserverTrait<R>) {
         if let Some(mut autoroute) = self.autoroute_walk(selection) {
             while autoroute.next(self, observer) {
                 //
@@ -134,7 +133,7 @@ impl<R: RulesTrait> Autorouter<R> {
         }
     }
 
-    pub fn autoroute_walk(&mut self, selection: &HashSet<NodeIndex>) -> Option<Autoroute> {
+    pub fn autoroute_walk(&mut self, selection: &Selection) -> Option<Autoroute> {
         Autoroute::new(
             self.ratsnest
                 .graph()
diff --git a/src/autorouter/mod.rs b/src/autorouter/mod.rs
index d9f3b2f..001b399 100644
--- a/src/autorouter/mod.rs
+++ b/src/autorouter/mod.rs
@@ -1,4 +1,5 @@
 mod autorouter;
 pub mod ratsnest;
+pub mod selection;
 
 pub use autorouter::*;
diff --git a/src/autorouter/selection.rs b/src/autorouter/selection.rs
new file mode 100644
index 0000000..5f6bcc7
--- /dev/null
+++ b/src/autorouter/selection.rs
@@ -0,0 +1,26 @@
+use std::collections::HashSet;
+
+use crate::layout::NodeIndex;
+
+#[derive(Debug, Clone)]
+pub struct Selection {
+    set: HashSet<NodeIndex>,
+}
+
+impl Selection {
+    pub fn new() -> Selection {
+        Self {
+            set: HashSet::new(),
+        }
+    }
+
+    pub fn toggle_at_node(&mut self, node: NodeIndex) {
+        if !self.set.insert(node) {
+            self.set.remove(&node);
+        }
+    }
+
+    pub fn contains(&self, node: &NodeIndex) -> bool {
+        self.set.contains(node)
+    }
+}
diff --git a/src/bin/topola-egui/overlay.rs b/src/bin/topola-egui/overlay.rs
index c0c2ce4..4eb4f36 100644
--- a/src/bin/topola-egui/overlay.rs
+++ b/src/bin/topola-egui/overlay.rs
@@ -5,7 +5,7 @@ use rstar::AABB;
 use spade::InsertionError;
 
 use topola::{
-    autorouter::ratsnest::Ratsnest,
+    autorouter::{ratsnest::Ratsnest, selection::Selection},
     drawing::{
         graph::{GetLayer, MakePrimitive},
         primitive::MakePrimitiveShape,
@@ -20,7 +20,7 @@ use topola::{
 
 pub struct Overlay {
     ratsnest: Ratsnest,
-    selection: HashSet<NodeIndex>,
+    selection: Selection,
     active_layer: u64,
 }
 
@@ -28,7 +28,7 @@ impl Overlay {
     pub fn new(layout: &Layout<impl RulesTrait>) -> Result<Self, InsertionError> {
         Ok(Self {
             ratsnest: Ratsnest::new(layout)?,
-            selection: HashSet::new(),
+            selection: Selection::new(),
             active_layer: 0,
         })
     }
@@ -73,23 +73,17 @@ impl Overlay {
         };
 
         if shape.contains_point(p) {
-            self.toggle_selection(node);
+            self.selection.toggle_at_node(node);
             return true;
         }
         false
     }
 
-    pub fn toggle_selection(&mut self, node: NodeIndex) {
-        if !self.selection.insert(node) {
-            self.selection.remove(&node);
-        }
-    }
-
     pub fn ratsnest(&self) -> &Ratsnest {
         &self.ratsnest
     }
 
-    pub fn selection(&self) -> &HashSet<NodeIndex> {
+    pub fn selection(&self) -> &Selection {
         &self.selection
     }
 }