According to the manufacturer this item is compatible with the following
· Worcester CDI 25 Combi
· Worcester CDI 30 Combi
· Worcester CDI 35 Combi
· Worcester CDI 40 Combi
· Worcester Greenstar 25CDI FSN NG Combi
· Worcester Greenstar 30CDI FSN NG Combi
· Worcester Greenstar 35CDI FSN NG Combi
· Worcester Greenstar 40CDI FSN NG Combi
· Worcester Bristish Gas 532I 32CDI FSN NG
· Worcester Bristish Gas 537I 37CDI FSN NG
· Worcester Bristish Gas 542I 42CDI FSN NG.