When making 10mm TRVs all the major manufacturers simply put a 15mm TRV together with a 15mm x 10mm reducer.
Usually it is cheaper to puchase these items seperatley.
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When making 8mm TRVs all the major manufacturers simply put a 15mm TRV together with a 15mm x 8mm reducer.
Usually it is cheaper to puchase these items seperatley.
..