Error CS0246

 using UnityEngine;
 
 
 public class LCVRSwapHMD : MonoBehaviour
 {
     [SerializeField] private LCVRPopupLabel label;
 
     private int hmdIndex = 0; // 0:hacosco dx 1:google cardboard 2:hacosco(single view)
 
     private void setHMDType(Camera eye, LCVRLens.HMD_TYPE hmdType){
         LCVRLens lens = eye.gameObject.GetComponent<LCVRLens>();
         if (lens != null) lens.HMDType = hmdType;
     }
 
     private void setViewModeAndHMDType(LCVRHead.VIEW_MODE viewMode, LCVRLens.HMD_TYPE hmdType){
         foreach (LCVRHead head in LCVR.Instance.Heads){
             head.ViewMode = viewMode;
 
             if (head.  LeftEye) setHMDType(head.  LeftEye, hmdType);
             if (head.CenterEye) setHMDType(head.CenterEye, hmdType);
             if (head. RightEye) setHMDType(head. RightEye, hmdType);
         }
     }
 
     private void updateHMD(){
         LCVRHead.VIEW_MODE viewMode = LCVRHead.VIEW_MODE.SIDE_BY_SIDE;
         LCVRLens.HMD_TYPE  hmdType  = LCVRLens.HMD_TYPE.HACOSCO_DX;
 
         string  name = null;
 
         switch (hmdIndex){
         case 0: name = "HACOSCO DX"      ; break;
         case 1: name = "Google Cardboard"; hmdType = LCVRLens.HMD_TYPE.GOOGLE_CARDBOARD; break;
         case 2: name = "HACOSCO (Single)"; hmdType = LCVRLens.HMD_TYPE.HACOSCO         ; viewMode = LCVRHead.VIEW_MODE.SINGLE; break;
         }
 
         setViewModeAndHMDType(viewMode, hmdType);
 
         label.Show(name);
     }
 
     public void OnClicked(){
         hmdIndex = (hmdIndex + 1) % 3;
         updateHMD();
     }
 
     private void Start(){ updateHMD(); }
 }

Please explain what the problem is and help fix it.