Valves - Misc. - BM SERIES 20 - 30 - 40 - 70 & 150. The monoblock valves of the BM series are characterized by a single body having following features. Low production costs Sound construction Compact size Reduced weight Valves of this kind are in general use when no auxiliary valve is needed and inside circuits are not so complicated that other kind of valves have to be utilised. Furthermore the inexistence of the rods and intermediate seals enables monoblock valves to have: More dependability Less constructive delicacy and fewer leak points Less maintenance Above characteristics suggest that monoblock valves should be used in the mobile machines field.