Saving color to PlayerPrefs

Im trying to save color to PlayerPrefs, but heard that you can easily save color to PlayerPrefsX. Well, the problem I have is that when im trying to use PlayerPrefsX it says that it is unknown identifier. Im using Javascript so can this be a problem here or should I use something else to save the color.

EDIT:

Here is saving:

#pragma strict

var rotatingEnemy : GameObject;

function Update () {
		if(Input.GetMouseButtonUp(0)){
	
			var hit : RaycastHit2D = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(Input.mousePosition), Vector2.zero);
			var hitObject = hit.collider;
			
			switch(hitObject.name){
				case "Background":
					break;
					
				default:
					PlayerPrefsX.SetColor("enemyColor", hitObject.renderer.material.color);
					rotatingEnemy.renderer.material.color = hitObject.renderer.material.color;
					break;
			}
		}
}

Here is loading:

function Start () {
	renderer.material.color = PlayerPrefsX.GetColor("enemyColor");
}

Error code:

Assets/scripts/Game/EnemyChangeColor.js(4,35): BCE0005: Unknown identifier: ‘PlayerPrefsX’.

and

Assets/scripts/ShopPreviewRotatingEnemyColor.js(16,41): BCE0005: Unknown identifier: ‘PlayerPrefsX’.

Looks like PlayerPrefsX isn’t loaded up correctly. Is the file named PlayerPrefsX.js and class named PlayerPrefsX?