My understanding is that sizing is more reliable in the 501 style jeans than the 505 or other zipflys so with that I ordered a pair of these. I have muscular 24" round thighs and my normal waist size is a 31, but ordering up to the 34 was helpful in giving me a bit more thigh room. The fabric feels durable and the material the patch is made out of does seem to be like cardboard, but that's okay in my book.