La Schréder GZM a été conçue en 1985 lors de la période des luminaires "trapèze" avec la VZ, RX, Z… It succeeded the GSO and its production stopped in around 2014.

The GZM consists of: An optical unit and a closing basin formed in a single piece of methyl methacrylate (the lower part is transparent while the upper part and the nose are opaque and gray in color), 'an aluminum reflector fixed to the optical unit, a double hook closure in stainless steel fixed to the upper part of the optical unit as well as a hinge pin which is fixed to it on the lower part and finally an end piece in injected aluminum alloy (and painted from 1997). A first generation in white color equipped with a closing system using a plate riveted to the basin was available for a very short period.  

The GZM is available in 3 different sizes:

• La GZM 90 pour lampe SOX 66W ou 90W : 920mm
• La GZM 135 pour lampe SOX 91W ou 135W : 1165mm
• La GZM 180 pour lampe SOX 131W ou 180W : 1510mm

After the cessation of production of the GSO, took over and therefore quickly became a great classic of Belgium. It is in Wallonia that we could find the most of it, it is still well established in Flanders but not as much as its sister the GZB. It is the 180 version which has sold the most for lighting major roads and motorways, the 90 and 135 remain very rare but can be found in areas, on small highways or even villages.

On the other hand, abroad, it is extremely rare, you can find some in France in Zebra version for pedestrian crossings.