What does EN166 FTKN mean on a smoke lens safety spectacle?
F confirms low energy impact resistance,
T confirms protection against high-speed particles at extreme temperatures,
K confirms the anti-scratch coating
and N confirms the anti-mist coating all meet EN166 requirements.
For outdoor plant operation and construction, the FT combination is important as it confirms the spectacle maintains impact protection across temperature extremes found on UK sites, from cold winter mornings to hot plant cabin environments.
What is the EN172 5-3.1 sun glare filter and why does it matter for site work?
EN172 is the standard for sun glare filters for industrial use. The 5-3.1 designation indicates a sun glare filter with a transmission factor of 3.1, which reduces the intensity of visible light reaching the eye. For plant operators, drivers and outdoor workers in bright UK conditions, sustained exposure to glare causes eye fatigue that impairs concentration and reaction time. The smoke lens addresses this without distorting colour rendering, so site signals, instrument readings and hazard markings remain clearly distinguishable.
Can this spectacle be worn while operating plant machinery?
Yes. The panoramic lens provides a wide unobstructed field of vision essential for cabin instrument visibility and external site awareness. The 25g lightweight construction prevents the ear and nose fatigue that causes operators to remove eyewear during long machine operation shifts, and the nonslip arms maintain a stable fit during vehicle movement. The EN172 5-3.1 filter reduces glare from reflective surfaces, wet ground and direct sunlight that are common hazards during plant operation.
Is there a clear lens version available?
Yes. The clear lens variant is the armourU K2 with product code AEYK2C, suitable for indoor tasks, low-light conditions, night driving and any application where light transmission reduction from a smoke lens would be a disadvantage. The smoke lens AEYK2S is the outdoor and bright-conditions variant. Both versions share the same EN166 FTKN rating, 25g weight, metal-free frameless design and TPE nose rest.
What is the maximum service life and when should the spectacle be replaced?
The maximum product life is two years. However, the spectacle must be replaced immediately if any scratching, pitting, crazing or damage to the lens is visible, regardless of age. Lens damage significantly reduces impact protection even if the lens appears functional. No parts are replaceable or interchangeable; if any component fails, the entire product must be discarded.
What is CMT ThinkGreen and how does this product support it?
CMT ThinkGreen is CMT Group's sustainability programme aimed at reducing environmental impact across the construction supply chain. The K2 contributes directly through its recycled polyester pouch, manufactured from two 1-litre plastic water bottles, and its recycled paper box. For sites operating under ISO 14001 or clients with net-zero supply chain commitments, specifying ThinkGreen-aligned products provides measurable, reportable progress. CMT Group is on track to meet its Net-Zero 50 objectives and regularly introduces sustainable product lines to help construction operations reduce procurement footprint without compromising on certified safety standards.
Why buy tinted safety eyewear from CMT Group?
Glare-related eye fatigue is a productivity and safety issue that most site PPE programmes underestimate until operatives start removing their eyewear on the job. CMT Group's armourU eyewear range is selected specifically for the UK construction and logistics market, where outdoor glare, temperature variation and extended shift lengths are the dominant comfort challenges. With the EDGE procurement portal, H&S managers can specify the correct lens variant by site type, preventing operatives from substituting indoor clear specs for outdoor tasks and vice versa, with full spend visibility and per-site budget controls.
Founded in 2010, CMT Group is the UK's largest independent site equipment supplier. Holding BSIF Registered Safety Supplier status means every armourU product on our platform has been verified to meet genuine certified safety standards, so procurement managers can specify with confidence rather than relying on unverified product claims.
