Renderer.bounds.extenct.x; cant find bounds

i was doing the Catch game pt1 scripts, and whenever i type renderer. <-- i cant find bounds and there is an error..

 float hatWidth = renderer.bounds.extents.x;

The whole thing

 using UnityEngine;
 using System.Collections;
 
 public class HatController : MonoBehaviour {
 
     public Camera cam;
 
     private float maxWidth;
 
 
     // Use this for initialization
     void Start () {
         if (cam == null) {
             cam = Camera.main;
         }
         Vector3 upperCorner = new Vector3 (Screen.width, Screen.height, 0.0f);
         Vector3 targetWidth = cam.ScreenToWorldPoint (upperCorner);
         float hatWidth = renderer.bounds.extents.x;
         maxWidth = targetWidth.x - hatWidth;
     }
     
     // Update is called once per Physics timestep
     void FixedUpdate () {
         Vector3 rawPosition = cam.ScreenToWorldPoint (Input.mousePosition);
         Vector3 targetPosition = new Vector3 (rawPosition.x, 0.0f, 0.0f);
         float targetWidth = Mathf.Clamp (targetPosition.x, -maxWidth, maxWidth);
         targetPosition = new Vector3 (targetWidth, targetPosition.y, targetPosition.z);
         transform.position = targetPosition;
     }
 }