The Express35 Duo Rig Configuration became wildly popular when ENDmedia shared their video review found here: https://cheesycam.com/express35-fig-rig-config-endmedia/. The video really showed that this setup proved to be really a lightweight, functional, tiny footprint stabilizer. The Duo setup was great, but if you're looking for that solid third point in stabilization, Express35 has now released a killer DSLR stabilizer 'Trio' setup.
The new 'foot' or 'pad' accessory added to the Duo setup can act as a shoulder rest or moved slightly for a chest pad. This adds a bit more to cost, but a whole lot more in functionality by adding that all important third point of contact. Most DSLR rig setups are built around a single design and don't easily function when broken apart. The nice feature about this configuration is that for the smallest footprint, the third point can be removed and the rig still functions as an excellent DSLR Stabilizer. Very nice modular thinking here. You might not find this new configuration on the website, so here's the direct link https://express35.com/run-n-gun-trio.
As usual you may want to drop Express35.com a comment that you found the information here. It never hurts..