BOSCH 9621 OE Fine Wire Double Iridium Spark Plug - Single

Did a tune up for my pruis. Everything was great and at a great price.

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!

So far so good. Fits perfectly on prius v 2013. Hoping it will last long for another 100k miles.

I read other reviews of this item about the Chinese ones being bad and German ones being great. So I figured I'd order 4 and see, well I got 4 Chinese ones so I returned them, didn't bother trying them as I didn't want a potential safety hazard.Ordered them end of March 2020 in Illinois, USA maybe other locations have German ones not sure.

Works for my 2019 Nissan Altima

Bought it for my Toyota Corolla 2009 LE and it fits well. I trust Bosch brand.

Apparently not compatible with a 2015 Mazda3. One of the 4 I ordered was defective. Received another today and after installing the engine ran extremely rough and couldn't keep a consistent idle. Reinstalled the original old plugs and runs fine. Unfortunately outside of return window. Waste of time and money.

Perfect fit for my Toyota