Em202/V visitors medium back chair structure is made of pressure diecast aluminium and transversal elements united in order to sustain and to keep stretched the elasticized mesh that form the seat. Polished aluminium finishes. Seat and backrest are made up of a single frame with elasticized mesh fixed to the aluminium structure. Back resistance adjust- ment according to user weight with side telescopic lever and antishock locking/unlocking device 5-spoke base in pressure die-cast aluminium, self return mechanism on the base.