diff --git a/src/types/debug.d.ts b/src/types/debug.d.ts
index b91d53e..3613e3f 100644
--- a/src/types/debug.d.ts
+++ b/src/types/debug.d.ts
@@ -18,7 +18,7 @@ declare namespace Debug {
   }
 
   interface LiquidPumpData {
-    index: number | undefined
+    index: string | undefined
     velocity: number | undefined
     direction: 'forward' | 'backward'
     volume: number | undefined
@@ -41,7 +41,7 @@ declare namespace Debug {
   }
 
   interface HeatArea {
-    index: number | undefined
+    index: string | undefined
     heatMotorData: HeatMotorData
     heatTemperature: HeatTemperature
     coldTrap: ColdTrap