Botpots is the main distributor of this brand in New Zealand and this is by far the best hand building clay I have came across with.
According to Potclays website Oxidising St. Thomas is:
Extremely popular general purpose high earthenware and stoneware body speckling very attractively under normal or slightly reducing conditions. Excellent resilience and tolerance. Good warp and crack resistance. Throws and slabs well. Outstanding for school use. Fires to toasted buff.
What I personally love about this is the plasticity as well as the ability to hold its shape even when pinched at a certian height and doesn’t collapse.
I highly recommend this if you specialize in hand building. This is a very good clay to work with. Fires at cone 10