diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 6c9a224..41dfb87 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/src/lib.rs b/src/lib.rs
index 8e193e8..7dfe022 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -61,6 +61,70 @@ impl TTS {
     }
 
     fn register(builder: &ClassBuilder<Self>) {
+        builder
+            .add_property("volume")
+            .with_getter(|this: &TTS, _| match this.0.get_volume() {
+                Ok(volume) => volume,
+                _ => 0.,
+            })
+            .with_setter(|this: &mut TTS, _, v: f32| {
+                let Features {
+                    volume: volume_supported,
+                    ..
+                } = this.0.supported_features();
+                if volume_supported {
+                    let mut v = v;
+                    if v < this.0.min_volume() {
+                        v = this.0.min_volume();
+                    } else if v > this.0.max_volume() {
+                        v = this.0.max_volume();
+                    }
+                    this.0.set_volume(v).expect("Failed to set volume");
+                }
+            })
+            .done();
+        builder
+            .add_property("min_volume")
+            .with_getter(|this: &TTS, _| {
+                let Features {
+                    volume: volume_supported,
+                    ..
+                } = this.0.supported_features();
+                if volume_supported {
+                    this.0.min_volume()
+                } else {
+                    0.
+                }
+            })
+            .done();
+        builder
+            .add_property("max_volume")
+            .with_getter(|this: &TTS, _| {
+                let Features {
+                    volume: volume_supported,
+                    ..
+                } = this.0.supported_features();
+                if volume_supported {
+                    this.0.max_volume()
+                } else {
+                    0.
+                }
+            })
+            .done();
+        builder
+            .add_property("normal_volume")
+            .with_getter(|this: &TTS, _| {
+                let Features {
+                    volume: volume_supported,
+                    ..
+                } = this.0.supported_features();
+                if volume_supported {
+                    this.0.normal_volume()
+                } else {
+                    0.
+                }
+            })
+            .done();
         builder
             .add_property("rate")
             .with_getter(|this: &TTS, _| match this.0.get_rate() {