---
product_id: 457717869
title: "NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/-"
brand: "ngk"
price: "$85.29"
currency: USD
in_stock: true
reviews_count: 5
category: "Ngk"
url: https://www.desertcart.us/products/457717869-ngk-cr9eix-iridium-ix-spark-plug-4-pack
store_origin: US
region: United States of America
---

# Iridium IX for superior ignition Enhanced power & performance Direct OEM replacement fit NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/-

**Brand:** ngk
**Price:** $85.29
**Availability:** ✅ In Stock

## Summary

> ⚡ Ignite your drive with NGK Iridium IX – Power that won’t quit!

## Quick Answers

- **What is this?** NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- by ngk
- **How much does it cost?** $85.29 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/457717869-ngk-cr9eix-iridium-ix-spark-plug-4-pack)

## Best For

- ngk enthusiasts

## Why This Product

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

## Key Features

- • **Perfect OEM Fit:** Direct replacement with original NGK packaging and hardware for hassle-free installation.
- • **Durability That Lasts:** Engineered for long-lasting performance, reducing maintenance frequency.
- • **Trusted Quality & Value:** Top-rated (#140 in Performance Spark Plugs) with 4.8-star reviews from 478 users.
- • **Precision Ignition Power:** Iridium IX electrode ensures faster, more reliable starts every time.
- • **Boosted Engine Efficiency:** Improves combustion for smoother acceleration and better fuel economy.

## Overview

The NGK CR9EIX Iridium IX Spark Plug 4-pack delivers premium ignition performance with a durable iridium electrode, ensuring faster starts and enhanced engine efficiency. Designed as a direct OEM replacement, it guarantees perfect fitment and long-lasting reliability, making it a top choice among automotive enthusiasts and professionals alike.

## Description

Genuine 4 pack NGK Iridium IX 3521 Spark Plug

Review: VALUE WAS GREAT FOR QUALITY. FIT WAS PERFECT START WAS RIGHT ON. POWER WAS IMPROVED. DURABLE AS IT SHOULD BE
Review: Good item would buy again

## Features

- 4 pack NGK Iridium IX 3521 Spark Plug
- Genuine NGK Parts
- Includes original packaging and hardware
- Direct replacement auto parts
- Confirm vehicle fitment with desertcart Confirmed Fit

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B004SKYAWM |
| Best Sellers Rank | #28,604 in Automotive ( See Top 100 in Automotive ) #140 in Automotive Performance Spark Plugs |
| Brand | NGK |
| Customer Reviews | 4.8 4.8 out of 5 stars (478) |
| Date First Available | 16 July 2021 |
| Item Weight | 127 g |
| Item model number | 3521 |
| Manufacturer | NGK |
| Manufacturer Part Number | CR9EIX |
| Model | 4 pack NGK Iridium IX 3521 Spark Plug |
| OEM Part Number | 7085731 |
| Position | Front, Rear |
| Product Dimensions | 8.41 x 2.39 x 8.43 cm; 127.01 g |

## Product Details

- **Brand:** NGK
- **Core material:** Iridium
- **Thread size:** 10mm
- **Top material type:** Iridium
- **Vehicle service type:** Car

## Images

![NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- - Image 1](https://m.media-amazon.com/images/I/61wBxBvQUhL.jpg)
![NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- - Image 2](https://m.media-amazon.com/images/I/61xGt1UU9GL.jpg)
![NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- - Image 3](https://m.media-amazon.com/images/I/51OGK696KIL.jpg)
![NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- - Image 4](https://m.media-amazon.com/images/I/51uBhtXk3NL.jpg)
![NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/- - Image 5](https://m.media-amazon.com/images/I/61CUnIeqKQL.jpg)

## Questions & Answers

**Q: Are these ngk 3521 cr9eix iridium ix spark plugs?**
A: These are correct and they perform flawlessly! Ron

**Q: Will these fit a 2019 polaris rzr turbo s**
A: To be safe: check with dealer or a cross reference app to be sure. Ron

**Q: Will this work on my Harley Davidson 2018 street glide special?**
A: I have a 2017 Road King with the Milwaukee 8 and this is the one it calls for.

**Q: Are these the right iridium plugs for an Indian scout 60?**
A: NGK has multiple grades of plugs that may fit your engine.  
It is recommended to go to NGK site at
https://ngksparkplugs.com/en/part-finder to verify the applications that will fit your engine.
This site will show you all of the available plugs to fit your engine and will also show you which grade plug is recommended for the best performance of your specific engine.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by M***. on 20 February 2026*

VALUE WAS GREAT FOR QUALITY. FIT WAS PERFECT START WAS RIGHT ON. POWER WAS IMPROVED. DURABLE AS IT SHOULD BE

### ⭐⭐⭐⭐⭐ Review
*by S***T on 23 August 2024*

Good item would buy again

### ⭐⭐⭐⭐⭐ Review
*by R***R on 30 November 2025*

They Look good ngk quality plugs

## Frequently Bought Together

- NGK CR9EIX - Iridium IX Spark Plug - 4-Pack/--
- K&N Motorcycle Oil Filter: High Performance, Premium, Designed to be used with Synthetic or Conventional Oils, Wrench Off Nut: Fits Select Suzuki Motorcycles, KN-138
- K&N Engine Air Filter: High Performance, Premium, Powersport Air Filter: Fits 2006-2010 SUZUKI (GSXR600, GSXR750) SU-7506

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-03-12*