My wife used this old-school glass Pyrex tube to make a perfect 3.5" round loaf of bread for a recent family dinner. She just oiled a loaf of frozen bread dough, dusted it with poppy seeds, slid it into the tube, let it rise, and baked it until golden brown. She slid it out of the tube and cut it into perfectly-sized (not over-sized!) slices. Topped with Irish butter, it was quite the treat.