Abstract: A new compression sprayer use a pop-up pressure gauge that has a transition piece that fits in a port on the tank. Threads on the transition piece hold it in place. The plunger cap that moves within the central passage is connected to a post, and is biased proximally by a spring that surrounds the post. The spring is held in place by a cover that is connected to the transition piece by interaction between a lock and a locking face. The distal end of the post serves as a pressure indicator, and may have a lateral lower surface that seats against the cap when the plunger cap is in a proximal position. One version of the plunger cap has a rigid proximal face that is integrally molded with the post, and has an o-ring that seals against the passage.