diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2438d88..779b7de 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,6 +12,26 @@ jobs:
       - run: ./examples/run_examples.sh
       - run: ./examples/example_crates/run_example_crates.sh
 
+  multi-targets-no-std:
+    name: multi-targets no_std
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target:
+          - x86_64-unknown-linux-gnu
+          - x86_64-unknown-none
+          - aarch64-unknown-linux-gnu
+          - aarch64-unknown-none-softfloat
+          - riscv64gc-unknown-none-elf
+          - riscv64imac-unknown-none-elf
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+          components: rustc, cargo
+      - run: cargo build --target ${{ matrix.target }} --no-default-features
+
   rustfmt-check:
     name: rustfmt check
     runs-on: ubuntu-latest
diff --git a/Cargo.toml b/Cargo.toml
index 83fa417..56467e8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,7 +6,7 @@ exclude = ["examples"]
 authors = [ "aarkegz <aarkegz@gmail.com>" ]
 license = "MIT"
 edition = "2021"
-version = "1.1.0"
+version = "1.2.0"
 repository = "https://github.com/GeminiLab/enumerable/"
 include = [
     "README.md",
@@ -33,4 +33,4 @@ std = ["enumerable_derive/std"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-enumerable_derive = { path = "enumerable_derive", version = "=1.1.0" }
+enumerable_derive = { path = "enumerable_derive", version = "=1.2.0" }
diff --git a/examples/example_crates/no_std/Cargo.toml b/examples/example_crates/no_std/Cargo.toml
index 3611bc2..2b9acaa 100644
--- a/examples/example_crates/no_std/Cargo.toml
+++ b/examples/example_crates/no_std/Cargo.toml
@@ -9,3 +9,8 @@ version = "0.1.0"
 
 [dependencies]
 enumerable = { path = "../../../", default-features = false }
+
+[profile]
+dev.panic = "abort"
+release.panic = "abort"
+
diff --git a/examples/example_crates/no_std/src/main.rs b/examples/example_crates/no_std/src/main.rs
index 534d6c8..54e6861 100644
--- a/examples/example_crates/no_std/src/main.rs
+++ b/examples/example_crates/no_std/src/main.rs
@@ -1,6 +1,6 @@
 //! This example tests the `Enumerable` derive macro in a `no_std` environment.
-
-#![no_std]
+//! 
+//! This example itself is not `no_std`, but it uses the `enumerable` crate with `default-features = false`.
 
 use enumerable::Enumerable;
 
diff --git a/src/impl_built_in.rs b/src/impl_built_in.rs
index bd50cab..1bfcb46 100644
--- a/src/impl_built_in.rs
+++ b/src/impl_built_in.rs
@@ -111,6 +111,26 @@ where
             self.inner.next().map(Some)
         }
     }
+
+    /// Implements the standard library's `Iterator::size_hint` method.
+    ///
+    /// This method returns the lower and upper bound of the iterator. For `OptionEnumerator`,
+    /// the bounds are adjusted to account for the `None` variant:
+    /// - If `self.first` is `true`, the lower bound is incremented by 1, and the upper bound
+    ///   is incremented by 1 (if it exists), to include the `None` variant.
+    /// - Otherwise, the bounds are directly derived from the inner enumerator.
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (lower, upper) = self.inner.size_hint();
+
+        if self.first {
+            (
+                lower.saturating_add(1),
+                upper.and_then(|u| u.checked_add(1)),
+            )
+        } else {
+            (lower, upper)
+        }
+    }
 }
 
 /// This is an implementation of the `Enumerable` trait for `Option<T>` where `T` is `Enumerable`.
diff --git a/src/lib.rs b/src/lib.rs
index 160619d..154b3e8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "std"), no_std)]
 #![doc = include_str!("./CRATE_DOC.md")]
 
 /// `Enumerable` is a trait for types that can have their possible values enumerated.
diff --git a/src/test/mod.rs b/src/test/mod.rs
index 297bb8f..63093ef 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -16,7 +16,7 @@ mod primitive {
 
     #[test]
     fn test_option_bool() {
-        assert_enumerator_eq(vec![None, Some(false), Some(true)]);
+        assert_enumerator_eq_with_size_hint(vec![None, Some(false), Some(true)]);
     }
 
     #[test]