Some coach sometime recommended wrapping a band in a figure 8 and putting it around your shoulders. Then you would "arch" into it as like a warm up, postural correction move.
The Slingshot being sleeved over your whole upper arm and across the whole chest must make it way better.
What about inverted rows (fat man chinups)?
1 arm rows with the other arm held static against the pull of the Slingshot?
Mark Bell seems cool. I hope he makes a fortune from all these things. Has anyone been to his gym?