diff --git a/CHANGELOG.md b/CHANGELOG.md
index b7cf7b4..c10b24b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@ See [GitHub releases](https://github.com/mll-lab/php-utils/releases).
 
 ## Unreleased
 
+## v4.1.0
+
+### Added
+
+- Add generics to `BaseRack` and its children
+
 ## v4.0.0
 
 ### Added
diff --git a/src/Tecan/Rack/AlublockA.php b/src/Tecan/Rack/AlublockA.php
index 03c39a1..52902b0 100644
--- a/src/Tecan/Rack/AlublockA.php
+++ b/src/Tecan/Rack/AlublockA.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class AlublockA extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/BaseRack.php b/src/Tecan/Rack/BaseRack.php
index a8da99d..8607dab 100644
--- a/src/Tecan/Rack/BaseRack.php
+++ b/src/Tecan/Rack/BaseRack.php
@@ -4,11 +4,12 @@
 
 use Illuminate\Support\Collection;
 
+/** @template TContent */
 abstract class BaseRack implements Rack
 {
     public const EMPTY_POSITION = null;
 
-    /** @var Collection<int, mixed> */
+    /** @var Collection<int, TContent|null> */
     public Collection $positions;
 
     public function __construct()
@@ -31,13 +32,13 @@ public function toString(): string
         ]);
     }
 
-    /** @param mixed $content Anything goes, null is considered empty */
+    /** @param TContent|null $content Anything goes, null is considered empty */
     public function assignFirstEmptyPosition($content): int
     {
         return $this->assignPosition($content, $this->findFirstEmptyPosition());
     }
 
-    /** @param mixed $content Anything goes, null is considered empty */
+    /** @param TContent|null $content Anything goes, null is considered empty */
     public function assignLastEmptyPosition($content): int
     {
         return $this->assignPosition($content, $this->findLastEmptyPosition());
@@ -71,7 +72,7 @@ public function findLastEmptyPosition(): int
         return $lastEmpty;
     }
 
-    /** @param mixed $content Anything goes, null is considered empty */
+    /** @param TContent|null $content Anything goes, null is considered empty */
     public function assignPosition($content, int $position): int
     {
         if (! $this->positions->has($position)) {
diff --git a/src/Tecan/Rack/DestLC.php b/src/Tecan/Rack/DestLC.php
index b0131c7..ce19fab 100644
--- a/src/Tecan/Rack/DestLC.php
+++ b/src/Tecan/Rack/DestLC.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class DestLC extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/DestPCR.php b/src/Tecan/Rack/DestPCR.php
index 109518a..303ef75 100644
--- a/src/Tecan/Rack/DestPCR.php
+++ b/src/Tecan/Rack/DestPCR.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class DestPCR extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/DestTaqMan.php b/src/Tecan/Rack/DestTaqMan.php
index c74e75d..9a89b7d 100644
--- a/src/Tecan/Rack/DestTaqMan.php
+++ b/src/Tecan/Rack/DestTaqMan.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class DestTaqMan extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/FluidXRack.php b/src/Tecan/Rack/FluidXRack.php
index aa74628..3e9ebb5 100644
--- a/src/Tecan/Rack/FluidXRack.php
+++ b/src/Tecan/Rack/FluidXRack.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class FluidXRack extends BaseRack implements ScannedRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/MPCDNA.php b/src/Tecan/Rack/MPCDNA.php
index 3041e6e..6d5b806 100644
--- a/src/Tecan/Rack/MPCDNA.php
+++ b/src/Tecan/Rack/MPCDNA.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class MPCDNA extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/MPSample.php b/src/Tecan/Rack/MPSample.php
index bc31fe2..b3a9f5d 100644
--- a/src/Tecan/Rack/MPSample.php
+++ b/src/Tecan/Rack/MPSample.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class MPSample extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/MPWater.php b/src/Tecan/Rack/MPWater.php
index 5440feb..b74835c 100644
--- a/src/Tecan/Rack/MPWater.php
+++ b/src/Tecan/Rack/MPWater.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class MPWater extends BaseRack
 {
     public function type(): string
diff --git a/src/Tecan/Rack/MasterMixRack.php b/src/Tecan/Rack/MasterMixRack.php
index 481c581..26d368c 100644
--- a/src/Tecan/Rack/MasterMixRack.php
+++ b/src/Tecan/Rack/MasterMixRack.php
@@ -2,6 +2,11 @@
 
 namespace MLL\Utils\Tecan\Rack;
 
+/**
+ * @template TContent
+ *
+ * @extends BaseRack<TContent>
+ */
 class MasterMixRack extends BaseRack
 {
     public function type(): string
diff --git a/tests/Tecan/Rack/RackTest.php b/tests/Tecan/Rack/RackTest.php
index efab38e..2f37f7b 100644
--- a/tests/Tecan/Rack/RackTest.php
+++ b/tests/Tecan/Rack/RackTest.php
@@ -62,7 +62,7 @@ public function testThrowsExceptionForInvalidPosition(): void
         $rack->assignPosition('Sample', $lastPosition + 1);
     }
 
-    /** @return iterable<string, array{BaseRack, string, string, int}> */
+    /** @return iterable<string, array{BaseRack<mixed>, string, string, int}> */
     public static function rackDataProvider(): iterable
     {
         yield 'MPCDNA' => [new MPCDNA(), 'MPCDNA', 'MP cDNA', 96];
@@ -76,7 +76,11 @@ public static function rackDataProvider(): iterable
         yield 'MPWater' => [new MPWater(), 'MPWasser', 'Trough 300ml MCA Portrait', 1];
     }
 
-    /** @dataProvider rackDataProvider */
+    /**
+     * @param BaseRack<mixed> $rack
+     *
+     * @dataProvider rackDataProvider
+     */
     #[DataProvider('rackDataProvider')]
     public function testRackProperties(BaseRack $rack, string $expectedName, string $expectedType, int $expectedPositionCount): void
     {