diff --git a/custom_components/xiaomi_home/miot/specs/spec_modify.yaml b/custom_components/xiaomi_home/miot/specs/spec_modify.yaml
index 73faea7..afca188 100644
--- a/custom_components/xiaomi_home/miot/specs/spec_modify.yaml
+++ b/custom_components/xiaomi_home/miot/specs/spec_modify.yaml
@@ -165,6 +165,11 @@ urn:miot-spec-v2:device:water-purifier:0000A013:roswan-lte01:1:0000D05A:
     unit: ppm
   prop.4.2:
     unit: ppm
+urn:miot-spec-v2:device:water-purifier:0000A013:yunmi-s20:1:  ## 云米泉先AI净水器Super Pro 1200G
+  prop.4.1:  # tds-in
+    unit: ppm
+  prop.4.2:  # tds-out
+    unit: ppm
 urn:miot-spec-v2:device:relay:0000A03D:lumi-c2acn01:1:
   prop.4.1:
     unit: kWh