Wat kind of armour are they wearing could it prevent arrows or slashing attacks?

I would guess that looks most like the iron buddas of the Jin dynasty of 12 century a.d ....

If so they were wearing lamellar armors but they usually wore more than one lair, the result is that they were pretty much imprevious to slashing and were only vunerable to the most powerful crossbows.

Though the big zhan ma daos with it's combined slash/blunt effect would still be devastating to them. that and fallng off a horse = =b

I suspect that they are intended to represent Mongol cavalry, as they seem to be inspired by some of the art in Stephan Turnbull's old The Mongols book from Osprey.

They are wearing lamellar. Most of it's black, so it is probably meant to represent lacquered leather; the officer at the far right is in iron armour of the same construction.

This kind of armor

The armour in the photos is Tibetan lamellar.

When were Tibetan troops at their height?

Cheers

In the 8th and 9th centuries. But this suit of armour was captured by Francis Younghusband's invasion of Tibet in 1905. The Tibetans were still using the same kind of armour that they had 1,000 years ago.

[Edit: I may be incorrect there. Read this thread for evidence about the extensive use of chain mail by 8th-9th century Tibetan armies: http://www.chinahistoryforum.com/index.php...wtopic=519&st=0 ]