The wake-up at 1 NT
It requires 10-12HCP and does not guarantee a stopper in the opening suit.
Of course, a stopper is preferable, but a wake up at 1 NT may often be the only one possible with 12HCP and if a double is impossible (for example with a doubleton in a major).
With a stronger balanced hand (14-16HCP) cstart by doubling and you'll bid NT in the next round, without a jump
The wake-uo at 2NT
This wake up at a high level requires 17-19HCP, and a solid stopper in the opening suit. Careful !
Do not confuse 2NT as an overcall (which shows a two-suiter with the with a wake-up bid of 2NT which is natural (17-19HCP).
cheapest suits)
The ideal hand for a 1NT wake up bidA : 12HCP and a solid stopper in the opening suit !