Table 9.

SRM fixed-point metals. The expanded uncertainty (k = 2) is denoted by U

SRM number	Metal	Fixed-point temperature (°C)	Unit size (g)	(mass fraction) %	U (mK)
743	Hg	−38.8344	680	99.999 999	0.15
1751	Ga	29.7646	200	99.999 995	0.04
1745	In	156.5985	200	99.999 99	0.12
741	Sn	231.928	1300	99.999 9	1.0
741a	Sn	231.928	200	99.999 97	0.25
740	Zn	419.527	350	99.999 9	1.0
740a	Zn	419.527	200	99.999 947	0.7
1744	Al	660.323	200	99.999 96	0.7
1746	Ag	961.78	300	99.999 974	1.1