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>

The .TS

 this.items = [];

 constructor(public navCtrl: NavController) {
     for(let i = 0; i < 2000; i++){    
       let item = {
         title: 'Title',
         body: 'body',
         avatarUrl: ''+i

nobody? plz help, im stuck in this