The concentrations of O, and O are indistinguishable between VSMOW and VSMOW2, and between SLAP and SLAP2. The specification sheet gives the standard errors in these measurements. The concentration of H is unchanged in VSMOW2 as well, but is slightly increased in SLAP2. The IAEA reports:
*  = , (Compare −428‰ for SLAP.)
On 6 July 2007, the tritium concentration was  TU in VSMOW2, and  TU in SLAP2.