Att.  Mr. 



                                                           nn.nnn  XXXXXXX         

                                                           ( xxxxxxx )



                                   Lleida,   __________ , ___th. of  20__



                                            GUARANTEE  LETTER


             By the present letter we guarantee that the use of our additive :

rb bertomeubeco F1/ASF for heavy fuel oil  in your co-generación plant, will not cause any damage in any elements that are component part of the engine combustion chamber and ducts of combustion exhaust gases, included turbocompressors.


            Likewise, the additive will not cause any contamination in the engine lubrication oil , wich was able to produce , as a consequence, any modification in the oil lubrication capacity nor in any other oil characteristics that could produce any damage in the engine.


            On the opposite, and if the responsability of our additive can be proved  without doubts , we will assume the reparing cost for the damage eventually produced in the above mentioned elements.


            This guarantee will be voided in case of incorrect use of our additive

rb bertomeubeco F1/ASF , not following our instructions of use and dose.




                                   Signed:           Rosendo Bertomeu

                                               General Manager



rb bertomeu, S.L.

Pol. Ind. Fondo de Llitera, Par. 82-83

E-22520 Fraga, Huesca (Spain)

Tel.:  +34 974 47 48 04 

+34 630 43 08 43