diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 33c4b1d..f090cec 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -4,7 +4,7 @@ kotlin = "2.0.0"
 bignum = "0.3.10"
 maven-publish = "0.29.0"
 
-calkt = "0.0.4"
+calkt = "0.0.5"
 
 [libraries]
 
diff --git a/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsMathParseOperand.kt b/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsMathParseOperand.kt
index 47d50af..5a6dab1 100644
--- a/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsMathParseOperand.kt
+++ b/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsMathParseOperand.kt
@@ -49,7 +49,7 @@ public class UnitsMathParseOperand(
             val unitKey = parseUnitKey(context)
 
             return UnitsExpression.Conversion(
-                value = MathExpression.Number(PreciseNumber.Companion.of(1)),
+                value = MathExpression.Number(PreciseNumber.of(1)),
                 key = unitKey
             )
         }
diff --git a/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt b/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt
index 69d4be2..8f725c1 100644
--- a/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt
+++ b/units/src/commonMain/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt
@@ -16,6 +16,8 @@ public fun interface UnitsParseUnitKeyFunction {
             context.token {
                 for (string in strings) {
                     if (context.startsWith(string)) {
+                        val nextChar = context.string.getOrNull(index = context.position + string.length)
+                        if (nextChar?.isLetter() == true) continue
                         context.drop(string.length)
                         return@UnitsParseUnitKeyFunction key
                     }
diff --git a/units/src/commonTest/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt b/units/src/commonTest/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt
new file mode 100644
index 0000000..b67c8b8
--- /dev/null
+++ b/units/src/commonTest/kotlin/me/y9san9/calkt/units/parse/UnitsParseUnitKeyFunction.kt
@@ -0,0 +1,33 @@
+package me.y9san9.calkt.units.parse
+
+import me.y9san9.calkt.Expression
+import me.y9san9.calkt.annotation.ExpressionSubclass
+import me.y9san9.calkt.calculate.CalculateResult
+import me.y9san9.calkt.parse.ParseContext
+import me.y9san9.calkt.parse.ParseResult
+import me.y9san9.calkt.parse.tryParse
+import me.y9san9.calkt.units.UnitKey
+import me.y9san9.calkt.units.annotation.UnitKeySubclass
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+
+class UnitsParseUnitKeyFunctionTest {
+    @Test
+    fun testDefaultImplementationChecksForNextChar() {
+        val function = create()
+
+        val result = tryParse("prefixtest") { context ->
+            function(context) as Expression
+        }
+        assertIs<ParseResult.Success<TestKey>>(result)
+        assertEquals(TestKey, result.value)
+    }
+
+    private fun create(): UnitsParseUnitKeyFunction {
+        return UnitsParseUnitKeyFunction.ofStrings(TestKey, "prefix", "prefixtest")
+    }
+
+    @OptIn(UnitKeySubclass::class, ExpressionSubclass::class)
+    private data object TestKey : UnitKey, Expression
+}