One China in theory, two in practice. For example, Taiwan has long had permission to buy almost leading edge US weapons systems that China would never get. Taiwan has purchased both Patriot and HIMARS missile systems. There is active discussion to let them buy Excalibur artillery rounds. Remember when F-35 deliveries were curtailed after it was discovered that some parts supplier had included Chinese magnets? The F-35 incorporates integrated circuits fabbed in Taiwan without any complaints.