<Tr> <Th_colspan="4"> Troy Weight (Used for precious metals) </Th> </Tr> <Tr> <Th> Unit </Th> <Th> Abbreviation </Th> <Th> Definition </Th> <Th> SI equivalent </Th> </Tr> <Tr> <Td> Grain </Td> <Td> gr </Td> <Td> </Td> <Td> 64.80 mg </Td> </Tr> <Tr> <Td> Pennyweight </Td> <Td> dwt </Td> <Td> 24 gr </Td> <Td> 1.555 g </Td> </Tr>

Which units belong to both the us and metric systems