diff --git a/core/src/main/scala/prometheus4cats/internal/package.scala b/core/src/main/scala/prometheus4cats/internal/package.scala
index 3c4a864..cd1d5bf 100644
--- a/core/src/main/scala/prometheus4cats/internal/package.scala
+++ b/core/src/main/scala/prometheus4cats/internal/package.scala
@@ -19,7 +19,7 @@ package prometheus4cats.internal
 import cats.data.NonEmptyList
 import cats.effect.kernel.{Clock, MonadCancelThrow, Resource}
 import cats.syntax.all._
-import cats.{FlatMap, Functor, Show}
+import cats.{Contravariant, FlatMap, Functor, Show}
 import prometheus4cats.OutcomeRecorder.Status
 import prometheus4cats._
 
@@ -143,6 +143,15 @@ object BuildStep {
   implicit class LabelsContravariantSyntax[F[_], M[_]: LabelsContravariant, A](bs: BuildStep[F, M[A]]) {
     def contramapLabels[B](f: B => A): BuildStep[F, M[B]] = bs.map(LabelsContravariant[M].contramapLabels(_)(f))
   }
+
+  implicit def auxContravariant[F[_], M[_]: Contravariant]: Contravariant[Aux[F, M, *]] =
+    new Contravariant[Aux[F, M, *]] {
+      override def contramap[A, B](fa: Aux[F, M, A])(f: B => A): Aux[F, M, B] = fa.map(_.contramap(f))
+    }
+
+  implicit class ContravariantSyntax[F[_], M[_]: Contravariant, A](bs: BuildStep[F, M[A]]) {
+    def contramap[B](f: B => A): BuildStep[F, M[B]] = bs.map(_.contramap(f))
+  }
 }
 
 sealed trait CallbackStep[F[_], A] { self =>
@@ -289,6 +298,8 @@ object MetricDsl {
           .map(_.contramapLabels[(Unit, OutcomeRecorder.Status)](_._2))
           .map(OutcomeRecorder.fromCounter)
       )
+
+    def contramap[B](f: B => A): BuildStep[F, Counter[F, B, Unit]] = dsl.map(_.contramap(f))
   }
 
   implicit class GaugeSyntax[F[_], A](dsl: MetricDsl[F, A, Gauge]) {
@@ -299,6 +310,8 @@ object MetricDsl {
           .map(_.contramapLabels[(Unit, OutcomeRecorder.Status)](_._2))
           .map(OutcomeRecorder.fromGauge(_))
       )
+
+    def contramap[B](f: B => A): BuildStep[F, Gauge[F, B, Unit]] = dsl.map(_.contramap(f))
   }
 }
 
diff --git a/docs/interface/dsl.md b/docs/interface/dsl.md
index f9edfe7..ac62f1d 100644
--- a/docs/interface/dsl.md
+++ b/docs/interface/dsl.md
@@ -140,7 +140,7 @@ unsafeLabelledCounter.build.evalMap(_.inc(3.0, labels))
 #### Simple Metric
 
 ```scala mdoc:silent
-val intCounter: Resource[IO, Counter[IO, Int]] = factory
+val intCounter: Resource[IO, Counter[IO, Int, Unit]] = factory
   .counter("counter_total")
   .ofLong
   .help("Describe what this metric does")
@@ -149,7 +149,7 @@ val intCounter: Resource[IO, Counter[IO, Int]] = factory
 ```
 
 ```scala mdoc:silent
-val shortCounter: Resource[IO, Counter[IO, Short]] = intCounter.map(_.contramap[Short](_.toInt))
+val shortCounter: Resource[IO, Counter[IO, Short, Unit]] = intCounter.map(_.contramap[Short](_.toInt))
 ```
 
 #### Labelled Metric
diff --git a/docs/metrics/derived-metric-types.md b/docs/metrics/derived-metric-types.md
index bb12c06..5e3d39a 100644
--- a/docs/metrics/derived-metric-types.md
+++ b/docs/metrics/derived-metric-types.md
@@ -32,7 +32,7 @@ operations.
 #### Obtaining from a `Histogram`
 
 ```scala mdoc:silent
-val simpleTimerHistogram: Resource[IO, Timer.Aux[IO, Histogram]] = factory
+val simpleTimerHistogram: Resource[IO, Timer.Aux[IO, Unit, Histogram]] = factory
   .histogram("time")
   .ofDouble
   .help("Records the how long an opertation took")
@@ -55,7 +55,7 @@ val labelledTimerHistogram: Resource[IO, Timer.Aux[IO, String, Histogram]] = fac
 #### Obtaining from a `Summary`
 
 ```scala mdoc:silent
-val simpleTimerSummary: Resource[IO, Timer.Aux[IO, Summary]] = factory
+val simpleTimerSummary: Resource[IO, Timer.Aux[IO, Unit, Summary]] = factory
   .summary("time")
   .ofDouble
   .help("Records the how long an opertation took")
@@ -76,7 +76,7 @@ val labelledTimerSummary: Resource[IO, Timer.Aux[IO, String, Summary]] = factory
 #### Obtaining from a `Gauge`
 
 ```scala mdoc:silent
-val simpleTimerGauge: Resource[IO, Timer.Aux[IO, Gauge]] = factory
+val simpleTimerGauge: Resource[IO, Timer.Aux[IO, Unit, Gauge]] = factory
   .gauge("time")
   .ofDouble
   .help("Records the how long an opertation took")
@@ -102,7 +102,7 @@ system time.
 #### Obtaining from a `Gauge`
 
 ```scala mdoc:silent
-val simpleCurrentTimeRecorderGauge: Resource[IO, CurrentTimeRecorder[IO]] = factory
+val simpleCurrentTimeRecorderGauge: Resource[IO, CurrentTimeRecorder[IO, Unit]] = factory
   .gauge("current_time")
   .ofDouble
   .help("Records the how long an opertation took")
@@ -142,7 +142,7 @@ To help disambiguate the difference in behaviour the `OutcomeRecorder` type will
 #### Obtaining from a `Counter`
 
 ```scala mdoc:silent
-val simpleOutcomeCounter: Resource[IO, OutcomeRecorder.Aux[IO, Long, Counter]] = factory
+val simpleOutcomeCounter: Resource[IO, OutcomeRecorder.Aux[IO, Long, Unit, Counter]] = factory
   .counter("outcome_total")
   .ofLong
   .help("Records the outcome of some operation")
@@ -164,7 +164,7 @@ val labelledOutcomeCounter:
 #### Obtaining from a `Gauge`
 
 ```scala mdoc:silent
-val simpleOutcomeGauge: Resource[IO, OutcomeRecorder.Aux[IO, Long, Gauge]] = factory
+val simpleOutcomeGauge: Resource[IO, OutcomeRecorder.Aux[IO, Long, Unit, Gauge]] = factory
   .gauge("outcome")
   .ofLong
   .help("Records the outcome of some operation")