---
product_id: 6985986
title: "Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery"
brand: "third rail"
price: "$0.48"
currency: USD
in_stock: true
reviews_count: 6
url: https://www.desertcart.us/products/6985986-third-rail-slim-protective-case-for-iphone-4-and-4s
store_origin: US
region: United States of America
---

# Lightweight & sleek Universal compatibility Thinnest battery case Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery

**Brand:** third rail
**Price:** $0.48
**Availability:** ✅ In Stock

## Summary

> 🔋 Power meets style in your pocket!

## Quick Answers

- **What is this?** Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery by third rail
- **How much does it cost?** $0.48 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/6985986-third-rail-slim-protective-case-for-iphone-4-and-4s)

## Best For

- third rail enthusiasts

## Why This Product

- Trusted third rail brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Bundle Up:** Get the complete Third Rail System for a streamlined power solution.
- • **Power On-the-Go:** Never run out of juice with the thinnest battery-enabled case available.
- • **Sleek & Stylish:** Elevate your iPhone 4/4S with a case that feels as good as it looks.
- • **Seamless Syncing:** Charge and sync effortlessly without removing the case.
- • **Versatile Compatibility:** Works flawlessly with all Third Rail Smart Batteries for ultimate convenience.

## Overview

The Third Rail Slim Protective Case for iPhone 4 and 4S is a lightweight, sleek case designed for everyday use. It features the thinnest battery-enabled design on the market, allowing for seamless charging and syncing without removal. Compatible with all Third Rail Smart Batteries, this case offers a perfect blend of protection and functionality.

## Description

From the Manufacturer          The Slim Case for iPhone 4 features sleek, low profile protection with a high-quality, soft touch feel. It is so thin and light, you'll hardly notice it's there! Understanding that your daily power needs may vary, this sleek everyday protective case is also enabled with the option, when needed, to slide on a Third Rail Smart Battery (sold separately) to extend your iPhone 4's usage time!  Third Rail iPhone 4 & 4S Slim Case (view larger). Product FeaturesLightweight, sleek everyday protective case with a soft-touch feelOptional Third Rail Smart Battery (sold separately or get the complete Third Rail System)Sync/charge without removing case (using included cable)Contrary to bulky traditional power cases, the Smart Battery slides on/off the case as neededWorks with iPhone 4 & 4SFAQWill this case work with all iPhone 4 models? Yes, this case is designed to work with all models of the iPhone 4. How is the Slim Case different than a traditional protective case? The Slim Case doubles as a traditional protective case and as a power case only when you need it. The Slim Case is Smart Battery compatible, meaning when low on power you can attach a Smart Battery (sold separately). When you no longer need additional power, remove the Smart Battery and enjoy your sleek, protective case.What are the three gold rails on my case? We have created the unique Third Rail System to seamlessly transfer power without the need for cords. When you attach a Smart Battery to your Slim Case, power is seamlessly transferred via the gold rails. Can I charge and sync my iPhone without removing my case? Yes! You can charge/sync your iPhone using the included micro-USB cable.  What's in the BoxSlim Case for iPhone 4, Micro-USB Cable, User's Manual  Third Rail iPhone 4 & 4S Slim Case (view larger).  Third Rail iPhone 4 & 4S Slim Case (view larger).

## Features

- Lightweight, sleek everyday protective case with a soft-touch feel
- Thinnest battery-enabled case on the market - Third Rail Smart Battery sold separately
- Sync/charge every iPhone 4 model without removing the case
- Third Rail Slim Case is compatible with all Third Rail Smart Batteries
- Third Rail System - Slim Case and Smart Battery bundle also available for purchase on desertcart.com

## Images

![Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery - Image 1](https://m.media-amazon.com/images/I/61XEjyj9fmL.jpg)
![Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery - Image 2](https://m.media-amazon.com/images/I/51QL2OLIXTL.jpg)
![Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery - Image 3](https://m.media-amazon.com/images/I/51+vg2W1lSL.jpg)
![Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery - Image 4](https://m.media-amazon.com/images/I/61k8zQaB8tL.jpg)
![Third Rail Slim Protective Case for iPhone 4 and 4S Compatible withThird Rail Fuel Universal Rechargeable External Smart Battery - Image 5](https://m.media-amazon.com/images/I/61iHyXLaaoL.jpg)

## Customer Reviews

### ⭐⭐⭐ 







  
  
    Two cases and 2 batteries gone through in 6 months
  

*by A***M on Reviewed in the United States on May 21, 2013*

Firstly, I must thank Third Rail (TR) support - they sent new batteries and tried to be helpful.Secondly, here are the pro's to the case (and system).- it is compact- it is intelligent - can charge other devices- it can be popped off and on very quickly.- multiple batteries can be combined or stacked.- the case is a good fit for the iPhone 4S.- the case protected my iPhone 4S very well.Finally, here are the cons,- it is proprietary- the battery hooks snap off over time - TR replaced two batteries.- the battery pops off the case without warning.- two cases failed on me. One had been dropped a few days earlier and the other just died a natural death- customer service seems to have gotten slower.Overall, I would recommend this only if the ability to stack the batteries and use it with other devices are very important for you.AM==== Updated ===As I said before - TR's support is beyond excellent. They back their products and replace defective ones very quickly. I cant praise them enough. However, the problems of battery popping off the case and the hooks snapping off remains due to the design.I did try the Mojo Vogue system but this one is FAR, FAR better than that.AM

### ⭐⭐⭐⭐ 







  
  
    Does the job, but easily detaches.
  

*by T***S on Reviewed in the United States on March 9, 2015*

Unit does the the job of storing and providing additional power.  It is also great that the battery is easily detachable from the outside of the phone without having to tear a bunch of parts off the phone to get at the expansion pack.My only downside: it is TOO easy to detach the battery.  It would be great if there was a locking mechanism or lever of some sort.  If you put the phone in a pocket or bag where it can get snagged on anything, then the chances are good that it will snag on the battery pack and pull the battery out of the "locked" position (if not off the phone).  This is a hassle when taking the phone in/out of any sort of bag (or purse, if you carry one).

### ⭐⭐⭐⭐⭐ 







  
  
    The best case out there
  

*by W***8 on Reviewed in the United States on December 7, 2011*

The case is beautiful and really thin. The added function of a attachable battery pack is wonderful its just great buy it! u wont regret! alot better den all those other rechargable cases u can get for iphone trust me

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-02-21*