Yes, Weems & Plath no longer market the Sirius LED flare. Sirius is themselves marketing
a newer version. A good guess is that W & P and Sirius simply could not agree on $.
As today's batteries
often have "expire" dates several years off, my personal stock of Duracell C (which both W & P and Orion use) expire in 2028. I see little reason to change batteries "yearly," and could foresee causing harm to the units by simply "messing with" them to open, replace batteries yearly and reassemble. After all, you can at least briefly test them by turning them on.