As noted above there is no such thing. It is simply chemically impossible.
Some products claim it, such as Brightwell Boost pH+, but it can only be due to one of two things:
1. Total ignorance on their part. They actually sell the same exact ingredient (hydroxide) in a different product (kalkwasser) and claim it boosts alk)
or
2. a scam designed to mislead reefers.
Neither gives one a reason to ever buy Brightwell products.
Their Boost pH+ nonsense:
"Boost pH+ High Range pH Increaser, raises pH only without increasing alkalinity or calcium (in tanks already having a proper dKH)
"Contains caustic sodium and potassium hydroxides in a proprietary base"
Their kalkwasser (has its own nonsense, but is correct about hydroxide adding alk):
" Calcium hydroxide is a caustic material;"
"Provides temporary alkalinity and helps maintain pH within the desired range when used as directed."