How to create a good service for your NSUserDefault Data (Local Storage)

NSUserDefault service

//
//  LocalStoreservices.swift
//
//  Created by Quentin De Quelen on 03/06/15.
//

import UIKit

struct LocalStore {
    //All Keys
    private static let authTokenKey = "authTokenKey"
    private static let userIdkey = "userIdkey"
    
    private static let userDefaults = NSUserDefaults.standardUserDefaults()
    
    //All setter
    static func setAuthTokenKey(token: String) {
        userDefaults.setObject(token, forKey: authTokenKey)
        userDefaults.synchronize()
    }
    static func setUserIdkey(id: String) {
        userDefaults.setObject(id, forKey: userIdkey)
        userDefaults.synchronize()
    }

    //All getter
    static func authToken() -> String? {
        return userDefaults.stringForKey(authTokenKey)
    }
    static func userId() -> String? {
        return userDefaults.stringForKey(userIdkey)
    }
    
    //All remover
    static func removeAuthTokenKey() {
        userDefaults.setObject("", forKey: authTokenKey)
        userDefaults.synchronize()
    }
    static func removeUserIdkey() {
        userDefaults.setObject("", forKey: userIdkey)
        userDefaults.synchronize()
    }
}