Moldex Pura-Fit vs SparkPlugs [Noise Reduction and Comfort Test]


The Moldex Pura-Fit (green) have been one of my favorite earplugs for several years now. They are easy to insert and exert just the right amount of pressure in my ears to stay put.

Most importantly, I get a good seal with them and they effectively reduce noise.

In this review, I am comparing the Pura-Fit to the slightly larger but equally popular Moldex SparkPlugs.

Included in this post are my own noise reduction test results and a comparison of size, comfort, and insertion ease.

Noise reduction (official and own results)

Official noise reduction ratings for these earplugs

The Pura-Fit (6800) and the SparkPlugs (6604) both have a U.S. noise reduction rating (NRR) of 33 decibels.

The NRR is a 10-person average obtained in a lab for the frequency range from 125 to 8000 Hz.

It was designed to allow users assess the suitability of a hearing protector for a particular high noise environment.

So as a hearing protector the Pura-Fit and the SparkPlugs are rated equal. 

But studies have shown that real world noise reduction for earplugs varies widely among different individuals.

You have a good chance of getting close to the NRR if:

  1. The earplugs have the right size and shape for your ear.
  2. You are able to completely insert your earplugs. Some foam earplugs expand rather fast after being rolled up, leaving users with little time to properly insert the plugs.

You also need to know that the noise reduction rating only takes frequencies down to 125 Hz into account.

The NRR isn’t the ideal yardstick if you are looking for earplugs to reduce disturbing low frequency noise.

Trucks, generators, and bass music all produce frequencies much lower than 125 Hz.

Personal noise reduction test for the Moldex Pura-Fit and SparkPlugs

Do the Pura-Fit or the SparkPlugs perform better for me?

To find out, I have done a detailed noise reduction test with narrow band noises at increasing frequencies using my own ears.

Low frequency noise can be a major annoyance factor, so I have tested down to 40 Hz (instead of 125 Hz as per the NRR).


With both earplugs I can get a good seal and they reduce noise well.

There isn’t much that separates the two, but for me the Pura-Fit are slightly more effective at a comfortable insertion depth.  

They are more effective at reducing higher low frequency noise (160 to 250 Hz) while the SparkPlugs perform a bit better against mid frequency noise.

Against high frequency noise both earplugs do equally well.


  • The Pura-Fit are already long earplugs, but the SparkPlugs top that.
  • If I insert them the SparkPlugs too deep, they become uncomfortable. A user with a very long ear canal could perhaps get more noise reduction by taking advantage of the complete length of the SparkPlugs.

The following table shows noise reduction averages (arithmetic, my ears)

Moldex Pura-Fit plus SparkPlugs noise reduction averages and examples

Noise reduction ranking

  1. Pura-Fit
  2. SparkPlugs


Noise reduction graph for the Pura-Fit and SparkPlugs (author’s ears)

Moldex Pura-Fit vs SparkPlugs Noise reduction chartEarplug size


The SparkPlugs are large and long, among the longest earplugs I have tried so far.

If large and long sounds like your ear canal, I would try the SparkPlugs.

However, if you have an average-size ear canal, I believe the Pura-Fit, which are already quite long, are better suited.

When I completely insert the SparkPlugs, they become uncomfortable after perhaps half an hour.

I have to keep the last 2-3 mm outside the ear canal. Then they work fine.

Moldex size comparison table

Note: If you have a very small ear canal, both earplugs may be too long, and in particular the SparkPlugs might exert too much pressure in your ears. In that case, check the post The 5 Best Earplugs for Small Ears.

Ease of insertion and comfort

The Pura-Fit and SparkPlugs are both easy to roll up and expand slowly, giving me enough time to insert them.

Both are made of PU foam with enough stiffness and can be rolled into a pointed shape. This makes it easy to wiggle them around canal bends.

But the SparkPlugs are thicker (and hence have more material) than necessary for my ears, so I have to compress them a lot more to get them in.

Moreover, because they are so long I have to pay attention that I don’t insert them too deep.

Once in the ear, I can forget the Pura-Fit after a few minutes. I find them very comfortable and can easily wear them for a whole day or night.

I can’t quite forget the SparkPlugs. While they are reasonably comfortable, they are a bit too big for my ears.

(More material compressed into the same diameter means more pressure in the ear canal. Alternatively, the earplugs become even longer.)

Ease of insertion ranking

  1. Pura-Fit
  2. SparkPlugs

Comfort ranking

  1. Pura-Fit
  2. SparkPlugs

Variations, bulk packaging and smaller quantities


Both the Pura-Fit and SparkPlugs are marketed as industrial earplugs and usually sold in larger quantities, such as boxes of 200 pairs (individually wrapped pairs) and even larger dispensers of unwrapped earplugs.

Don’t let the term industrial deter you from trying these earplugs for sleeping, studying and other non-industrial purposes.

The Pura-Fit are among the most comfortable NRR-33 foam earplugs I have come across so far.

Some distributors sell trial packs. I recommend starting with a trial pack.

Here are some examples:

Pura-Fit (6800) 25 pairs and Pura-Fit 50 pairs.

SparkPlugs (6604) 25 pairs.

Unless they are from dispenser packs, the Pura-Fit (6800) come individually packaged in pairs (small paper pouches) and the SparkPlugs (6604) in small plastic bags.

I prefer the paper pouches. They are easy to open and less of an environmental burden.

Both earplugs are also available in corded versions: the Pura-Fit 6900 and the SparkPlugs 6654.


While both are fine earplugs, I prefer and recommend the Pura-Fit. They are easy to insert, reduce noise well, and are very comfy.

I would say they are excellent earplugs for average-size ear canals.

The SparkPlugs are also easy to insert and reduce noise about as well as the Pura-Fit, but they are a bit too big for me.

It all depends on the size of your ear canal: If yours is long and large and you find most earplugs too small, the SparkPlugs could work better for you than the Pura-Fit.

If you have a very small ear canal, you may find both earplugs too long. In that case, read my post The 5 Best Earplugs for Small Ears for smaller options.

For low-frequency noise reduction, both earplugs are good but not great. For this type of noise, I have had better results with cylindrical foam earplugs.

Read the post How to Make Your Earplugs Block More Low Frequency Noise for more details.

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