Not getting checkbox value in view

  addUserDetails(userDetails : UserDetails){

const ud = this.userDetailsRef.push({
  userName :this.userDetails.userName,
  userAge : Number(this.userDetails.userAge),
  fName : this.userDetails.fName || null ,
  gender : this.userDetails.gender,
  date :,
  uLocation : this.userDetails.uLocation,
  description : this.userDetails.description,
  language1 : this.userDetails.language1 || null,
  language2 : this.userDetails.language2 || null,
  language3: this.userDetails.language3 || null,
 options : this.userDetails.options
<ion-list *ngFor = "let op of options">
    <ion-checkbox [(ngModel)] = "op.checked" name="options"></ion-checkbox>
{{}} {{op.value}}

i’m getting the array values when i mouse-over on that object but i don’t know why i am not able get those values in output. i mean in view page also i’m not able to get those check boxes.