The present invention relates to variants of serine proteases having decreased immunogenicity relative to their corresponding wild-type proteases. Sidewall spacers are formed such that an upper portion of the line sidewall is exposed so as to react with a refractory metal to form a low resistance silicide. The gate electrode can be a schottky contact or an insulated metal contact. The current collectors are electrically insulated from the sealing flange and cover by a gasket, and extend outwards from the flange for electrical attachment to a load. A brake status input device receives a brake signal. 33 mgf^3 and a Gurley air resistance equal or greater than 50 seconds100 ml.