Physics2D.OverlapBox is smaller than Gizmo

Hii!

So I have a problem with my script where the Gizmo is a bit larger than the OverlapBox. I have dealt the size of the gizmo because I read in another post that the OverlapBox deals in halfs or something. Neither works.

Please lend me aid in this, its driving me mad!

public class CheckRooms : MonoBehaviour
{

    public float enemyCount;
    public Vector2 checkRange;

    private void Update()
    {
        CheckRoom();
    }

    void CheckRoom()
    {
        enemyCount = 0;
        Collider2D[] countEnemies = Physics2D.OverlapBoxAll(gameObject.transform.position, checkRange, LayerMask.GetMask("EnemyLayer"));
        foreach (Collider2D enemy in countEnemies)
        {
            Debug.Log(enemy.gameObject.name);
        }
    }
    void OnDrawGizmosSelected()
    {

        Gizmos.color = Color.blue;
        Gizmos.DrawCube(gameObject.transform.position, checkRange / 2);
    }
}