the NYPD ESU vest are custom made in ballistic lvl 3 called "turtle neck"
which is destined to be replaced with the new Hornet vest, which is basically a law enforcement version of the U.S.M.C. Modular Tactical Vest (MTV).
The OCCB of NYPD has just accuquired these new vest and set to assist ESU in case of a Mumbai style terror attack on the NYC soil.
Items are carried differently by the ESU members depends on their role, some carry extra ammos and some carry medicals.