diff --git a/src/value.rs b/src/value.rs
index 75d8261..f155d54 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -71,6 +71,9 @@ pub type ArrayType<F> = SmallVec<[F; 4]>;
 /// # }
 /// ```
 ///
+/// Vectors can have arbitrary length and are represented as `Val::Array(SmallVec<[F; 4]>)`. That
+/// is, a vector always consists of floats. Vectors of bools or ints do not exist. Further, 
+/// 4 elements are stored on the stack, and if more are needed, they are stored on the heap.
 /// An example with vectors is shown in the following.
 ///
 /// ```rust