T800 is a fiber. It can be woven into fabric or used in UD tape.

And why the hell can’t you post all of your composite questions in the same forum?

@SWComposites, apology for that. I have deleted the thread in other forum.

T800 is fiber. T800H is dry fabric; T800S is unidirectional tape. So, I expect for the modulus for two directions should be quite close to each other, right?

No.
T800 is generic fiber name.
T800H is T800 fiber with H type sizing/surface treatment
T800S is T800 fiber with S type sizing/surface treatment
Or something like that. If you need details, call you Toray sales rep.

I just looked it up. S and H are not different sizings, as would be be a logical assumption. They are different fibers with similar, but not the same, properties. One difference is one is "never twisted" and the other is "untwisted". This is a subtle, but significant distinction. Untwisted fiber was at some prior time twisted fiber.

Both types are carbon tow, not fabric. One type is probably preferred for fabrics use. Fabrics are usually solution impregnated, and highly collimated carbon fibers may not soak-up enough solution to reach target resin content. Twisting and untwisting tow disrupts the collimation and increases the bulk of the fabric, slightly.

Cp - thanks, I forgot about the whole: twist, untwisted, never twisted fiber variants.

I have checked with my vendor whether they are fabricating it for fabric and also checking with Toray as well.

I might have confused from the website that T800H common application is weaving by T800H is fabric...