diff --git a/lib/solaar/cli/show.py b/lib/solaar/cli/show.py
index a516a76d..2e7af542 100644
--- a/lib/solaar/cli/show.py
+++ b/lib/solaar/cli/show.py
@@ -149,18 +149,21 @@ def _battery_line(dev):
         print("     Battery status unavailable.")
 
 
+def _level_kind(level):
+    """Distinguish a real percentage ("level") from a qualitative approximation."""
+    if isinstance(level, BatteryLevelApproximation):
+        return "approximation"
+    if isinstance(level, int):
+        return "level"
+    return None
+
+
 def _battery_json(battery):
     """Serialize a Battery as a JSON-friendly dict, or None if unavailable."""
     if battery is None:
         return None
     level = battery.level
-    if isinstance(level, BatteryLevelApproximation):
-        # A qualitative level (e.g. "good"), not an actual percentage
-        level_kind = "approximation"
-    elif isinstance(level, int):
-        level_kind = "level"
-    else:
-        level_kind = None
+    next_level = battery.next_level
     status = getattr(battery.status, "name", None)  # canonical member name; combined flags have none on Python < 3.11
     if status is None and battery.status is not None:
         # Decompose combined flags into single-bit members so the output
@@ -173,8 +176,9 @@ def _battery_json(battery):
         )
     return {
         "level": int(level) if level is not None else None,
-        "level_kind": level_kind,
-        "next_level": int(battery.next_level) if battery.next_level is not None else None,
+        "level_kind": _level_kind(level),
+        "next_level": int(next_level) if next_level is not None else None,
+        "next_level_kind": _level_kind(next_level),
         "status": status,
         "voltage": battery.voltage,
     }
@@ -193,8 +197,8 @@ def _receiver_json(receiver):
 
 def _device_json(dev):
     """Serialize a device as a JSON-friendly dict, or None if the device is gone."""
-    # Save the descriptor-known protocol; the ping below may update it, and
-    # for an offline device the ping fails and would leave it unset.
+    # Save the descriptor-known protocol before the ping below updates it; for
+    # a descriptor-less device the property itself pings to determine it.
     protocol = float(dev.protocol) if dev.protocol else None
     try:
         online = dev.ping()
@@ -211,7 +215,7 @@ def _device_json(dev):
         "name": dev.name,
         "number": dev.number,
         "receiver": _receiver_json(receiver),
-        "pid": str(dev.wpid or dev.product_id),
+        "pid": str(dev.wpid or dev.product_id).upper(),  # hex, uppercase (product_id case varies by hid backend)
         "path": dev.path,
         "bluetooth": dev.bluetooth,
         "mac": dev.hid_serial if dev.bluetooth else None,
diff --git a/tests/solaar/cli/test_show_json.py b/tests/solaar/cli/test_show_json.py
index 9f7f914a..72d7a864 100644
--- a/tests/solaar/cli/test_show_json.py
+++ b/tests/solaar/cli/test_show_json.py
@@ -82,6 +82,13 @@ class DeviceInfoStub:
 
 pi_4066 = {"wpid": "4066", "kind": NamedInt(1, "keyboard"), "serial": "5678", "polling": "4ms", "power_switch": "left"}
 
+
+@pytest.fixture(autouse=True)
+def _reset_device_instances():
+    yield
+    Device.instances[:] = []
+
+
 responses_receiver = [
     fake_hidpp.Response("000000", 0x8003, "FF"),
     fake_hidpp.Response("000300", 0x8102),
@@ -114,6 +121,7 @@ def test_battery_json_percentage():
         "level": 55,
         "level_kind": "level",
         "next_level": None,
+        "next_level_kind": None,
         "status": "DISCHARGING",
         "voltage": 3800,
     }
@@ -123,6 +131,7 @@ def test_battery_json_approximation():
     info = _battery_json(_battery(BatteryLevelApproximation.GOOD))
     assert info["level"] == 50
     assert info["level_kind"] == "approximation"
+    assert info["next_level_kind"] is None
 
 
 def test_battery_json_full_approximation():
@@ -130,6 +139,7 @@ def test_battery_json_full_approximation():
     assert info["level"] == 90
     assert info["level_kind"] == "approximation"
     assert info["next_level"] == 20
+    assert info["next_level_kind"] == "approximation"
 
 
 @pytest.mark.parametrize(
@@ -182,7 +192,14 @@ def test_device_json_online():
     assert info["kind"] == "keyboard"
     assert info["protocol"] == 4.5
     assert info["online"] is True
-    assert info["battery"] == {"level": 18, "level_kind": "level", "next_level": 52, "status": None, "voltage": None}
+    assert info["battery"] == {
+        "level": 18,
+        "level_kind": "level",
+        "next_level": 52,
+        "next_level_kind": "level",
+        "status": None,
+        "voltage": None,
+    }
 
 
 def test_device_json_direct_usb_device():