The props used are also listed at the bottom of the description of the class (if you are watching on the website). It says "What You'll Need: MAT." 

Hi Alison, ahhh yes Thankyou!  

Why didn't I know about stretching like this? Definitely enjoyed this, but  I did have a bit of sacral pain with penultimate pose (up on the block), but I modified a touch to get the most out of it. (My cat slept between my legs and she is like a cinder-block, my body contorting.)  I have been applying your joint rotations (moving the knee out to the sides in semi-circles) to cycling. We get stuck in place in also tension-filled shapes, and also over-tense muscles quads and hips in serious efforts. Very curious to explore more about this. Thanks!