BOSCH 9621 OE Fine Wire Double Iridium Spark Plug - Single

I placed an order for two Spark Plugs for AUDI A4 B5 however, I have received two spark plugs which one is larger and thinner than the other. I need either the order for the missing spark plug or a refund. I believe the the thin long one will not match the car. Please see the photo

We purchased these spark plugs for our 2015 Mazda CX-5, and they were fully compatible with the vehicle. Installation was straightforward and beginner-friendly, making it a manageable project even for those with limited automotive experience. Prior to replacing the spark plugs, our Mazda was experiencing noticeable hesitation and displaying a cylinder 1 misfire code. After installing this set, the issue was completely resolved, and the vehicle has been running smoothly ever since. The product met our expectations in terms of quality, performance, and overall value. One detail worth noting is that although the listing may suggest a single item, the package actually includes a complete set of four spark plugs, which was a pleasant surprise. I did not take photos of the new spark plugs, but I have included a picture of the worn-out plugs that were removed from the vehicle for reference. Overall, I would recommend this product to anyone looking for a reliable replacement. If engine issues persist after installation, it may indicate a different underlying mechanical problem rather than an issue with the spark plugs themselves.

Very good quality

Fit my 2009 Maxima.

Installed on 2009 Corolla. Gas mileage has improved by 2 mpg. You will need a 9/16" spark plug socket (https://www.amazon.com/gp/product/B004FEPFSY) for a 2009 - 2014 Corolla. The skirting around the top of the hood prevents you from using a single long extension to remove the old plugs. Instead, I had to use 2 small extensions, attaching the spark plug socket to one small extension, then adding another extension when the spark plug socket and first small extension were down in the cylinder. Because of the skirting around the hood and the fact that you have to use multiple small extensions, you cannot simply replace the plugs using the 9/16" plug socket. The extensions will separate in the cylinder before the plug socket comes free. Instead, use a piece of flexible tubing from a hardware store to reinstall the new spark plugs. The tubing you get should allow the white part of the plug to go up into the tube and not allow the plug to fall out when held vertically. You don't want to just drop the new plugs in the cylinders because the spark gap can be moved due to an impact with the bottom of the cylinder. Hope this helps!