Fibras y Elastómeros S.A. (FYESA) is the direct successor of manufacturing activities begun in 1895 by Francisco Montero Loizaga, grandparent of the present company's CEO, in the field of thermal insulation and sealing materials.

At present FYESA is focused in the production and sales of sealing products for industrial fluid handling systems:
BELPA compressed gasket sheets for flanged joints.
MONTERO mechanical packings for valves, pumps and other equipment
.BELPAFLEX expansion joints

FYESA is also involved in the manufacture of BARLAN boards and textiles for thermal insulation, and is a distributor of UCAR Carbon's GRAFOILexpanded graphite products. MONTERO sells over 45 countries around the world.
Certified to ISO 9002 by Lloyds, with its own rubber, textile and paper technological base, FYESA's is equipped to perform tests on gasket materials along the latest standards ( DIN 28090, prEN 13555 ) both for R&D work on new product development and for customer application support.
In Portugal and Spain the sales organisation covers the whole territory. Important end users and OEMs are serviced directly by FYESA own sales force. A network of specialised distributors, with FYESA's technical assistance, attend with their local stocks to the needs of the main areas of demand.
Sales in other European markets are made through specialised agents, distributors and technical wholesalers. FYESA has achieved a well established presence in some Latin American countries, and has established in 1999 a manufacturing base in Mexico, in order to intensify its action in those markets.