diff --git a/Benchmarks/Package.swift b/Benchmarks/Package.swift
index 2745ea6..7e4c352 100644
--- a/Benchmarks/Package.swift
+++ b/Benchmarks/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 import PackageDescription
 
diff --git a/Package.swift b/Package.swift
index e45bc6a..5963314 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.7
+// swift-tools-version: 6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
diff --git a/Sources/AsyncChannels/Select.swift b/Sources/AsyncChannels/Select.swift
index 7d66672..3aad52f 100644
--- a/Sources/AsyncChannels/Select.swift
+++ b/Sources/AsyncChannels/Select.swift
@@ -17,7 +17,7 @@ protocol SelectProtocol {
 }
 
 @usableFromInline
-struct ReceiveHandler<T>: SelectProtocol {
+struct ReceiveHandler<T: Sendable>: SelectProtocol {
     
     private var chan: Channel<T>
     private let outFunc: (T?) async -> ()
@@ -59,7 +59,7 @@ struct NoneHandler: SelectProtocol {
 }
 
 @usableFromInline
-struct SendHandler<T>: SelectProtocol {
+struct SendHandler<T: Sendable>: SelectProtocol {
     private var chan: Channel<T>
     private let val: T
     private let onSend: () async -> ()
diff --git a/Tests/AsyncChannelsTests/AsyncChannelTests.swift b/Tests/AsyncChannelsTests/AsyncChannelTests.swift
index 525455f..815d38e 100644
--- a/Tests/AsyncChannelsTests/AsyncChannelTests.swift
+++ b/Tests/AsyncChannelsTests/AsyncChannelTests.swift
@@ -15,10 +15,11 @@ final class AsyncTest: XCTestCase {
     
     func failAfter(duration: Duration) -> Channel<Bool> {
         let stop = Channel<Bool>()
+        let sleepSig = sleep(for: .seconds(1))
         Task {
             await select {
                 receive(stop)
-                receive(sleep(for: duration)) {
+                receive(sleepSig) {
                     XCTFail("Test timed out")
                     exit(1)
                 }
@@ -615,7 +616,7 @@ final class AsyncTest: XCTestCase {
         a.close()
     }
     
-    class SomeData {
+    final class SomeData: Sendable {
         let name: String
         let age: Int
         
@@ -769,4 +770,40 @@ final class AsyncTest: XCTestCase {
         
         XCTAssertEqual(100, sum)
     }
+    
+    func testStopSig() async {
+        
+        enum StopSignal {
+            case error
+            case done
+        }
+        
+        let data = Channel<String>()
+        let signal = Channel<StopSignal>()
+        
+        
+        Task {
+            var done = false
+            while !done {
+                await select {
+                    receive(data) { print($0!) }
+                    receive(signal) {
+                        switch $0! {
+                        case .error:
+                            print("there was an error")
+                            done = true
+                        case .done:
+                            print("done processing data")
+                            done = true
+                        }
+                    }
+                }
+            }
+            print("done!")
+        }
+        
+        await data <- "foo"
+        await data <- "bar"
+        await signal <- .done
+    }
 }