How can I buy replacement trouser pockets the right size?

I've seen several ads for replacement sew-on, or iron-on trouser pockets, but none show the sizes. I want replacements for gents trouser pockets with maximum dimensions 6 inches wide by maximum drop of 12 inches. Can anyone help?
Bill Matthews, February 2018


done
Why not do what I did and make some from scratch?

Gdgeheu, February 2018