diff --git a/Sources/FirebladeECS/UnorderedSparseSet.swift b/Sources/FirebladeECS/UnorderedSparseSet.swift
index 5a3d2b9..977b113 100644
--- a/Sources/FirebladeECS/UnorderedSparseSet.swift
+++ b/Sources/FirebladeECS/UnorderedSparseSet.swift
@@ -17,10 +17,6 @@ public class UnorderedSparseSet<Element> {
     internal var dense: ContiguousArray<Entry>
     internal var sparse: [Index: Key]
 
-    // TODO: implement
-    // a) RandomAccessCollection conformance
-    // b) subscript
-
     public init() {
         sparse = [Index: Key]()
         dense = ContiguousArray<Entry>()
@@ -148,6 +144,7 @@ extension UnorderedSparseSet: MutableCollection, RandomAccessCollection {
             }
             return element
         }
+
         set(newValue) {
             insert(newValue, at: position)
         }
diff --git a/Tests/FirebladeECSTests/SparseSetTests.swift b/Tests/FirebladeECSTests/SparseSetTests.swift
index 403e438..993899e 100644
--- a/Tests/FirebladeECSTests/SparseSetTests.swift
+++ b/Tests/FirebladeECSTests/SparseSetTests.swift
@@ -508,4 +508,35 @@ class SparseSetTests: XCTestCase {
         XCTAssertEqual(string, "Hello World")
 
     }
+    
+    func testSubscript() {
+        let characters = UnorderedSparseSet<Character>()
+        
+        characters[4] = "H"
+        characters[13] = "e"
+        characters[44] = "l"
+        characters[123] = "l"
+        characters[89] = "o"
+        
+        characters[66] = " "
+        characters[77] = "W"
+        characters[55] = "o"
+        characters[90] = "r"
+        characters[34] = "l"
+        characters[140] = "d"
+        
+        XCTAssertEqual(characters.count, 11)
+        
+        XCTAssertEqual(characters[4], "H")
+        XCTAssertEqual(characters[13], "e")
+        XCTAssertEqual(characters[44], "l")
+        XCTAssertEqual(characters[123], "l")
+        XCTAssertEqual(characters[89], "o")
+        XCTAssertEqual(characters[66], " ")
+        XCTAssertEqual(characters[77], "W")
+        XCTAssertEqual(characters[55], "o")
+        XCTAssertEqual(characters[90], "r")
+        XCTAssertEqual(characters[34], "l")
+        XCTAssertEqual(characters[140], "d")
+    }
 }