It's not rocket science - VISM KPM Short Vertical Grip/ Keymod & M-lok & Picatinny Mount

This short vertical grip works fine. I bought another low profile one, as well, but it has a picatinny mount. Problem is my rifle has an mlok lower rail. So you make sure you know your rail. This one works. You brace against it and the handrail together. It was inexpensive, yet it works as well as any expensive grip. Optic planet had a good selection of products for my rifle, priced high and low.