New Guard for HCS-007

I need a new guard for my electric shaver.

I got a TransformU HCS-007 5V — 1A in a box. its great with a bunch of tools and sprays to keep clean, but the four guards happen to jump from a 6mm to a 9mm (And having the right length shave for my face was the original reason to get the new shaver).

Even with adjustable lengths, my facial hair is all over the place, so the lowest on 6mm makes it patchy, and the highest on 9mm doesn't really cut anything. It sucks.

So what do I need in order to get a new guard? Just measurements? Same brand? Same style? I learned shaving on my own and it is yet to be a fruitful endeavour. I'm investing for the far future I guess

pls send help