These belt pouches (descriptions and prices) are made with a one-piece calf back and front flap. Calf is strong and light, reducing the weight. Fronts are Poetsch & Peterson latigo and shoe/bridle cowhide - relatively firm leathers. The fronts are slightly larger than the calf backs and when they are saddle-stitched by hand through a welt seam strip of bridle leather to the calf back they stretch it taut, like the skin of a drum head.
The importance of saddle-soaping and dubbin & how to apply them
Saddle-Stitching
Tanning methods and the danger of using chromium-tanned leathers
Repairs
Is leather just a byproduct of the meat industry?