diff --git a/src/Categories/Category/Instance/Thinnings.agda b/src/Categories/Category/Instance/Thinnings.agda
new file mode 100644
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+++ b/src/Categories/Category/Instance/Thinnings.agda
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+{-# OPTIONS --safe --without-K #-}
+
+module Categories.Category.Instance.Thinnings where
+
+open import Categories.Category.Core
+open import Categories.Category.Helper
+open import Data.List.Base using (List)
+open import Relation.Binary.PropositionalEquality
+
+open import Thinning
+open import Thinning.Properties
+
+Thinnings : ∀ {a} (A : Set a) → Category a a a
+Thinnings A = categoryHelper record
+  { Obj = List A
+  ; _⇒_ = Thinning A
+  ; _≈_ = _≡_
+  ; id = id
+  ; _∘_ = _∘_
+  ; assoc = assoc _ _ _
+  ; identityˡ = identityˡ _
+  ; identityʳ = identityʳ _
+  ; equiv = isEquivalence
+  ; ∘-resp-≈ = cong₂ _∘_
+  }