Myson 2TRVADAP adapts older Myson thermostatic radiator valves for TRV 2 WAY heads with M30 (30mm) thread. The male thread on the top of the adaptor is M30 (30mm) and the female thread on the bottom is M28 (28mm). Myson TRVs have used M30 threads for a long time, in 1997 they changed their M28 heads to M30 hence the need for this adapter.
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