diff --git a/Prometheus-and-WMI-CounterTypes.md b/Prometheus-and-WMI-CounterTypes.md
index 3331984..5341ba5 100644
--- a/Prometheus-and-WMI-CounterTypes.md
+++ b/Prometheus-and-WMI-CounterTypes.md
@@ -20,28 +20,31 @@ This applies to WMI classes inheriting `Win32_PerfRawData`.
 | `PERF_COUNTER_OBJ_TIME_QUEUELEN_TYPE` | `gauge`         |                                      |
 | `PERF_COUNTER_COUNTER`                | `counter`       |                                      |
 | `PERF_COUNTER_BULK_COUNT`             | `counter`       |                                      |
-| `PERF_RAW_FRACTION`                   | `gauge`         |                                      |
-| `PERF_COUNTER_TIMER`                  | `counter`       | Units are "high-resolution performance counter"                                 |
-| `PERF_PRECISION_SYSTEM_TIMER`         | `counter`       | Units are "system performance timer"                                     |
+| `PERF_RAW_FRACTION`                   | `gauge`         | Verify units. Numerator. Goes with `PERF_RAW_BASE`                                     |
+| `PERF_COUNTER_TIMER`                  | `counter`       | PerfTime, normalise to seconds.      |
+| `PERF_PRECISION_SYSTEM_TIMER`         | `counter`       | PerfTime, normalise to seconds.      |
 | `PERF_100NSEC_TIMER`                  | `counter`       | Normalize to seconds (`value / 1e7`)                                    |
 | `PERF_PRECISION_100NS_TIMER`          | `counter`       | Normalize to seconds (`value / 1e7`) |
 | `PERF_OBJ_TIME_TIMER`                 | `counter`       | Object-specific units                |
 | `PERF_PRECISION_OBJECT_TIMER`         | `counter`       | Object-specific units                |
-| `PERF_SAMPLE_FRACTION`                | 2x`gauge`       | Verify units                         |
-| `PERF_COUNTER_TIMER_INV`              |                 |                                      |
-| `PERF_100NSEC_TIMER_INV`              |                 |                                      |
-| `PERF_COUNTER_MULTI_TIMER`            |                 |                                      |
-| `PERF_100NSEC_MULTI_TIMER`            |                 |                                      |
-| `PERF_COUNTER_MULTI_TIMER_INV`        |                 |                                      |
-| `PERF_100NSEC_MULTI_TIMER_INV`        |                 |                                      |
-| `PERF_AVERAGE_TIMER`                  |                 |                                      |
-| `PERF_ELAPSED_TIME`                   |                 |                                      |
-| `PERF_COUNTER_NODATA`                 |                 |                                      |
-| `PERF_AVERAGE_BULK`                   |                 |                                      |
-| `PERF_SAMPLE_BASE`                    |                 |                                      |
-| `PERF_AVERAGE_BASE`                   |                 |                                      |
-| `PERF_RAW_BASE`                       |                 |                                      |
-| `PERF_PRECISION_TIMESTAMP`            |                 |                                      |
-| `PERF_LARGE_RAW_BASE`                 |                 |                                      |
-| `PERF_COUNTER_MULTI_BASE`             |                 |                                      |
-| `PERF_COUNTER_HISTOGRAM_TYPE`         |                 |                                      |
+| `PERF_SAMPLE_FRACTION`                | `gauge`         | Verify units. Numerator. Goes with `PERF_SAMPLE_BASE` |
+| `PERF_COUNTER_TIMER_INV`              | `counter`       | Inactive time. PerfTime, normalise to seconds |
+| `PERF_100NSEC_TIMER_INV`              | `counter`       | Inactive time. Normalize to seconds (`value / 1e7`) |
+| `PERF_COUNTER_MULTI_TIMER`            | Many `counter`  | PerfTime, normalise to seconds       |
+| `PERF_100NSEC_MULTI_TIMER`            | Many `counter`  | Normalize to seconds (`value / 1e7`) |
+| `PERF_COUNTER_MULTI_TIMER_INV`        | Many `counter`  | Inactive time. PerfTime, normalise to seconds |
+| `PERF_100NSEC_MULTI_TIMER_INV`        | Many `counter`  | Inactive time. Normalize to seconds (`value / 1e7`) |
+| `PERF_AVERAGE_TIMER`                  | `summary`       | Verify units. The `_count` is the `_Base` |
+| `PERF_ELAPSED_TIME`                   | `gauge`         | PerfTime, normalise to seconds. Convert to unixtime?           |
+| `PERF_COUNTER_NODATA`                 | ??              | Error value?                         |
+| `PERF_AVERAGE_BULK`                   | `summary`       | `_sum` part. Goes with `PERF_AVERAGE_BASE`                        |
+| `PERF_SAMPLE_BASE`                    | `gauge`         | Verify units. Denominator. Goes with `PERF_SAMPLE_FRACTION` |
+| `PERF_AVERAGE_BASE`                   | `summary`       | `_count` part. Goes with `PERF_AVERAGE_BULK` |
+| `PERF_RAW_BASE`                       | `gauge`         | Verify units. Denominator. Goes with `PERF_RAW_FRACTION` |
+| `PERF_PRECISION_TIMESTAMP`            |  `counter`      | PerfTime, normalise to seconds       |
+| `PERF_LARGE_RAW_FRACTION`                 |  `counter`      | Verify units. Numerator. Goes with `PERF_LARGE_RAW_FRACTION` |                                                                           
+| `PERF_LARGE_RAW_BASE`                 |  `counter`      | Verify units. Denominator. Goes with `PERF_LARGE_RAW_FRACTION` |                                                                           
+| `PERF_COUNTER_MULTI_BASE`             |  `counter`      | Seems to be a time denominator. Drop. |
+| `PERF_COUNTER_HISTOGRAM_TYPE`         |  ??             | No docs.                              |
+
+To convert "PerfTime" units to seconds, divide by the result of `QueryPerformanceFrequency()`.
\ No newline at end of file