NPU Green

NPU Green is a top-quality fibreboard ensuring excellent performance. Entirely made of pure cellulose fibres, without added dyes, it has a 5.5-7.0 pH, is 100% recyclable and fully degrades within 3-6 months, depending on its thickness, without polluting the environment. The origin of the raw material is FSC and PEFC certified (see Sustainability section).
In order to keep its characteristics unaltered, the cellulose is vulcanized using natural substances only, no chemical or synthetic products.
Thanks to its superlative features, it allows to obtain heel seat linings which are the stiffest, lightest and most performing ever.

Being made of natural fibres only, with no added adhesives, dyes or other chemical products, NPU Green DOES NOT BURN DURING LASERING, thus leaving the insole clean and without those soot residues that usually make recycled cardboards dirty.

(Lasered NPU Green)

(Lasered standard shankboard)

The processing of NPU Green is really exceptional as it guarantees an extremely precise shaping that is maintained over much longer time. Its fibres have a structure similar to those of a fabric and ensure a higher resistance to both torsion and failure, as well as to screws and nails.


NPU Green was designed to satisfy the needs of extreme strength and stability, such as in women’s shoes with very high and/or ‘island’ platforms, with very short and narrow heels, even when mounted using threaded bushings in a very backward position, impossible to reach with a steel shank.
Over time we have found out one employment that makes it absolutely incomparable to any other cardboard for mounting insoles: the production of INSOLES WITHOUT STEEL SHANK, PERFECT FOR BOTH MEN’S AND WOMEN’S SHOES, EVEN WITH HIGH HEELS

(NPU Green man insole without metal shank)

(NPU Green woman high heel insole without metal shank)

(NPU Green insole without metal shank – detail)

The shank absence in the insoles also offer the following undeniable advantages:
– as the position and the dimension of the steel shanks can basically be ignored, heels can be fixed wherever desired;
– there are no restrictive regulations to conform with, such as the Chinese GB 28011, which concerns only the shanks but not the insoles in which they are inserted;
– it avoids the presence of that typical bulge in the insole lower part that can disturb the heel presence, thus allowing a perfect support of their base, regardless of their length, and keeping the bar intact.
It also does not alter the soles line, allowing to avoid the insole roughing, saving time and obtaining a cleaner and smoother shoe bottom part.

(Differences between insoles with and without metal shank)

Besides having gone through tightness tests carried out at Cimac, this innovative solution has been tested by a large group of women – of different age, weight and height – who have been wearing 100 mm heel court décolleté shoes without steel shank for more than eight months, without highlighting any critical issues.

Instead, they shared enthusiastic opinions regarding the following:
1. shoes are lighter and, consequently, make you less tired, especially considering how many steps you take during the day, and thus reduce the impact on muscles. In fact, a NPU Green insole made without steel shank weighs 30% less than one made of traditional materials and with shank;
2. the shoes don’t set metal detectors off, thus allowing a smooth walk-through. This can be very interesting not only for those who travel a lot by plane, but especially for those who, for work, must go daily to courts, bureaus and all those places where metal detectors are required;
3. the shoes convey a feeling of stability. Walking, especially in high heels, stresses the back of the shoe (the trunk), most of all transversally. An insole made of NPU Green ensures a transversal resistance superior to any other material usually used, even without steel shank, considering that the latter contributes much more to the insole longitudinal resistance than to the transversal one.

(High heel woman shoe (100mm) without metal shank)