How to split the objects in the inventory

 using System;
 
 [Serializable]
 public class ISItem
 {
     public int Id;
     public string Name;
 
 
 }

   [Serializable]
 public class ISWeapon : ISItem
 {
     public int Damage;
     public int Level;
 
     public ISWeapon(int id, string name, int damage, int level)
     {
         Id = id;
         Name = name;
         Damage = damage;
         Level = level;
     }
 }
 
     
 [Serializable]
 public class ISArmor : ISItem
 {
     public int Armor;
     public int ArmorSpeedMod;
 
     public ISArmor(int id, string name, int armor, int mass)
     {
         Id = id;
         Name = name;
         Armor = armor;
         ArmorSpeedMod = mass;
     }
 }

 
 public class ISItemList : MonoBehaviour {
 
     public static List<?????> WeaponList = new List<??????>();
 
 }
 

How i can add objects(ISArmor, ISWeapon and other) to List List = new List(); or array????