Bistable structures in nature are unparalleled for their fast response and force amplification even with the most minute physical stimula-tion. However, current works on bistable structures mainly focus on their stable states, while promising intermediate states with a large range of tunable energy barriers are missing. Here, we report a type of ultra-tunable bistable structure. Our results show that the trigger force of a single structure can be tuned to 0.1% of its maximum value, and the lifted weight difference exceeds 107 times using grip-pers composed of proposed structures with different design param-eters. We prototyped various functional robots using the proposed structures to demonstrate their wide-range design space across ma-terials and scales, such as an ultra-sensitive robotic flytrap, a fast catcher, a minimal jumper, etc. This work broadens the frontiers of bistable structure design and leads a way to future design in robotics, biomedical engineering, architecture, and kinetic art.