From the Sacred Seltzer website:
Get crunk on Christ! Sacred Seltzer contains 95% real holy water* and 5% alcohol.
*Blessed according to the official Catholic procedure on March 31, 2022 in LA County, CA
Sacred Seltzer is a product of the art/marketing collective MSCHF; unfortunately, they only made one batch, and it's already sold out. That's probably for the better — both Uproxx and Input reviewed the hard holy seltzer and said it was not that great, even with the obligatory caveat of "being a hard seltzer."