VirtualScroll loading all

hello guys… Im having trouble with this VirtualScroll,
it is loading all the content… but i would like to just load 5 or 10 items… any help?
take a look at the scroll… is very big

  <ion-list [virtualScroll]="items" [bufferRatio]="'5'">
    
       <ion-item *virtualItem="let item">
              <ion-avatar item-left>
                <ion-img [src]="item.avatarUrl"></ion-img>
              </ion-avatar>
          
              <h2>{{item.title}}</h2>          
              <p>{{item.body}}</p>
    
       </ion-item>
    
  </ion-list>

The .TS

 this.items = [];

 constructor(public navCtrl: NavController) {
     for(let i = 0; i < 2000; i++){    
       let item = {
         title: 'Title',
         body: 'body',
         avatarUrl: 'https://avatars.io/facebook/random'+i
       };    
       this.items.push(item);
 
   }}

nobody? plz help, im stuck in this