Love the penlight form factor! I am wearing office attire, so 1xAA be too bulky while 1xAAA has short runtime. With this Klarus Penlight P20, it will blend in nicely with the pen that I carry in my shirt's pocket, plus it has a long run time with 2xAAA & high output. This will come in handy when I do stock checking in warehouse. Seems like a good "Bite light" too. Thanks.