The shares come off an effective shelf-registration, so the buyers get freely tradeable stock on settlement rather than restricted stock. A placement agent finds buyers quietly over a day or two; the deal is announced after pricing.
Because the buyers can sell immediately, registered directs are often followed by heavy supply at the offer price. On micro caps they are frequently accompanied by warrants, which layers future dilution on top of today's.
Example: a $3.10 stock sells 20M registered shares at $2.75 plus one warrant per share at $3.25. The raise is $55M, share count rises by 20M now and potentially 20M more later.
Related: private-placement, shelf-registration, pipe-deal, dilution, warrant