Conan sighed. "Professor, the darts you put in my watch are small; can't you fit more than one? It'd be really useful, especially when there are multiple perps, or if I miss a shot."
"Sorry, my boy, but there isn't enough space to create a re-load system. Besides, this way you'll use them sparingly. You've managed with one so-far, and do you know the unit price of each dart?"
"Five Yen?"
Professor Agasa shook his head. "Nine-hundred."
"…. That's expensive for something so small."
"Strong paralytics are costly, and you use one nearly daily. It adds up, Shinichi-kun."
"Point taken."