ISI Seat especially designed for auditorium, theatres and conference halls. Seat and backrest made of MDF, 16mm thick, finished with beech plywood and 2 layers of polyurethane varnish. Upholstery of seat and backrest made of open-cell polyurethane foam, covered with M-1 fireproof fabrics with an additional underlying M-1 layer. Both fabrics and fireproof layer comply with legal regulations UNE-EN 1021: 1994, part 1 & 2. Sidearms made of high density waterproof MDF panels, 60mm thick, finished either with beech plywood and 2 layers of polyurethane varnish, or covered with M-1 fireproof fabrics just like seat and backrest. They also enclose the folding pivot mechanisms, which allow the seat pan to fold. Pivot mechanisms are made of injected polyamide, very resistant to mechanical demands, and do not require maintenance. The left pivot mechanism generates the automatic reversion when the user stands up, by means of a torsion spring. The right pivot mechanism acts as a structural component. There is a shock absorber inside it which applies an opposite strength to the spring, thus providing a smooth movement when the seat folds. Fixing to the floor is achieved by means of a base set, 6mm thick, finished with epoxy powder coating, black colour.