I use such razors. I had a folding handle, now a kamisori. These are pretty good quality products.
Blades for them made in China are not very high quality. They are inexpensive, rather soft (and some consider them dumb), but enough to shave 1-2 times. These blades are interchangeable with the original, made in Japan (Pen). The difference in length is 1 mm (49 versus 50), but they fit perfectly on the fasteners, 1 mm does not play a role.
In general, I am very pleased with the purchase of these razors.
Blades for them made in China are not very high quality. They are inexpensive, rather soft (and some consider them dumb), but enough to shave 1-2 times. These blades are interchangeable with the original, made in Japan (Pen). The difference in length is 1 mm (49 versus 50), but they fit perfectly on the fasteners, 1 mm does not play a role.
In general, I am very pleased with the purchase of these razors.