This board was designed by WifiCable and assembled by us, I'm selling these boards so that everyone can get them, with her permission! Here's her description of it:

Want to get the most out of your 8th/9th gen Lenovo Tiny? Tiny(a)riser is a custom PCIe riser that exposes a hidden PCIe link, enabling configurations not possible before! It's compatible with the ThinkCentre M720q, M920q, M920x and ThinkStation P330 Tiny, and lets you use a low profile PCIe card and an extra M.2 NVMe SSD at the same time.

This is possible because the riser slot on the motherboard actually contains two PCIe links, one x8 link and one x4 link. The x8 link comes from the CPU and was meant for GPU equipped models, while the x4 link comes from the PCH and was meant for the Thunderbolt and NIC equipped models. Lenovo made two different risers for these configurations, only using one link at a time, but this riser gives you both PCIe links at once! The two links are completely independent and are able to function at the same time.

Using this riser, you can install a low profile PCIe card just as you can with the stock risers, and add an extra M.2 NVMe SSD in addition to the onboard ones. The SSD is tucked away near the front of the machine, plugged into a right angle M-key M.2 slot that holds the SSD firmly in place. Due to an unfortunate non-removable standoff placement on the motherboard, only 2230, 2242 and 2260 size SSDs fit comfortably. It is possible to get a 2280 drive to fit if you try hard enough, but the fit will be suboptimal.

I've successfully tested this riser on my own M720q where it works 100% perfectly with x1, x4, x8 and x16 cards, and it will work just as well on the other machines that share this motherboard, the M920q, M920x and P330 Tiny.

It was not possible to fit a screw mount in the spot the stock risers have it, so it's technically a bit less securely mounted, but, as long as the machine doesn't get bumped too hard (like, really hard, I tried and you have to shake it around a lot for it to come out), the riser will stay in place.

Note that the M.2 slot only supports PCIe NVMe M-key or B+M-key drives, not SATA based ones.