diff --git a/hardware/arduino/water_level/water_level.ino b/hardware/arduino/water_level/water_level.ino
index a391630..c584032 100644
--- a/hardware/arduino/water_level/water_level.ino
+++ b/hardware/arduino/water_level/water_level.ino
@@ -29,6 +29,12 @@
 // 12-inch: 400-2000 ±20%
 //         Ref Resistance 2000 ±20%
 //         Active Length  12.4" (315mm)
+// 15-inch: 400-2500 ±20%
+//         Ref Resistance 2500 ±20%
+//         Active Length 15.3" (389mm)
+// 18-inch: 400-3000  ±20%
+//         Ref Resistance 3000  ±20%
+//         Active Length: 18.3" (465mm)
 // 24-inch: 400-4000 ±20%
 //         Ref Resistance 4000 ±20%
 //         Active Length  24.34" (618mm)