1. Annular Blowout Preventer (Spherical BOP) is designed and fabricated in accordance with API 16A. 2. Blowout Preventer Stack Blowout Preventer (API 16A BOP) Stacks are the main wellhead pressure control equipment for oil and gas drilling, no matter onshore or offshore drilling. Blowout preventer stack consists of annular blowout preventer, single ram blowout preventer, double ram blowout preventer and drilling spool. Blowout preventer stacks designed and fabricated in accordance with API 16A are similar to Shaffer's BOP or Cameron's BOP.
