I took mine to a little electronics store. My First Wife just informed me we did take some to a grocery store for testing and buying replacements there.
I remember car radios u burned a lot of OZ4 tubes...
IIRC they were the size of a woman’s little finger.
Hey, I'm old enough to remember when there were local drug stores! I bought my first car and motorcycle with the proceeds from doing the floors and windows in said drug store. Later on, I turned old enough to get a driver license. Later on, I sold the street bike and bought a dirt bike to ride out in the desert. Later on, I took to walking in the desert. Later on, I just drove out there to shoot rifles at targets. Nowadays, I look at pictures of the desert, through trifocals, poorly.
I used to be great with iron sights. Thank goodness for Leupold, Aimpoint, and covered ranges!