HTML

[(ngModel)] in a select

<select name="miselect" [(ngModel)]="seleccionados" multiple="multiple">
    <option [value]="item" *ngFor="let item of lista">{{item}}</option>
</select>

angular select ((ngmodel selected))

[ngValue]="Var" my variable in typescript.components to verify ID  
<select type="number" [(ngModel)]="selectedLevel">
  <option *ngFor="let level of levels" [ngValue]="Var">{{level.name}}</option>
</select>