Why the Cut Resistance (Second Digit) in EN 388 is Often Marked "X"

The Core Reason: Outdated Test vs. Advanced Materials

In short: The traditional EN 388 blunt blade test fails to accurately measure the true performance of modern high-performance cut-resistant materials, causing the test to be declared "invalid."

1.  The Specific Triggers for an "X"

According to the EN388 standard, the traditional cut test result is declared invalid ("X") if any of the following occur:

Excessive Blade Dulling: The blade becomes so worn during a single sample test that it can no longer effectively cut the standard calibration canvas (the cycles needed increase beyond 80% of its initial value).

Blade Damage: Hard components in the material (e.g., steel wires, glass) cause the blade to chip, notch, or degrade severely.

Conclusion: An "X" does NOT mean the glove has no cut resistance. On the contrary, it strongly indicates that the glove material is so cut-resistant that it "broke" the old test.

2. Why is "X" So Common?

Modern High-Performance Materials:

Ultra-High-Molecular-Weight Polyethylene (UHMWPE): e.g., Dyneema®, Spectra® (very slick, high hardness).

Para-aramid: e.g., Kevlar® (extremely high strength).

Glass Fiber/Steel Composites: Very high hardness.

These materials are designed to resist sharp blades, and their properties cause rapid dulling of the EN 388's blunt blade.

The Solution in EN 388: The CPM Test

To solve the "X" problem, EN 388:2016 introduced a mandatory alternative test method: the CPM Test (Coup Test with a Rotating Circular Blade).

CPM Test Principle: Uses a sharp, rotating circular blade under a fixed load. It measures the number of rotations needed to cut through the sample.

Key Improvements:

The blade is continuously sharp and rotating, eliminating the blade-dulling issue.

Results are stable, repeatable, and perfectly suited for high-hardness fibers.

How It Appears on the Label:
If a sample gets an "X" in the traditional test, it must undergo the CPM test.
The code will look like this: (4, X, 2, 1,  F)

The X in the second position means the traditional test was invalid.

The final letter F (or A-E) is the CPM Cut Resistance Level. This is the glove's true, scientifically valid cut performance rating.

Practical Guide: What to Do When You See an "X"?

Here is a clear decision-making process for interpreting the label:

Key Advice for Buyers and Users:

Never interpret "X" as "zero protection." It usually means "exceptional protection, beyond the old test's scope."

Always look for the CPM Level: E.g., EN388:4X43F means a CPM Cut Level of F (highest).

Cross-reference with the ANSI Level: High-performance gloves will also show an ANSI cut rating (A1-A9). If a glove has an "X" in EN 388 but a high ANSI rating (e.g., A7, A8, A9), it is undoubtedly a top-tier cut-resistant glove.

Ask the supplier: If the label only shows an "X" without a CPM level, request the full EN 388 test report to confirm the CPM test result.

Summary Table

Final Takeaway: The "X" in EN 388 cut resistance is a "good problem to have." It signals that material technology has advanced beyond the capabilities of the old test. As a user, treat it as a prompt to look for more scientific data (the CPM Level or ANSI Level), not as a negative mark.