Buy a standard wrist roller if you want, but a homemade version of PVC pipe (1.5 to 2 inches is perfect) with climbing webbing attached is a cheap and amazing solution.
Check our power-rack version that we made out of aluminum tubing. The beauty of it in a rack is that you can truly test the grip without the shoulders giving out first.
With squats, fear is often the limiting factor. Part of us is afraid that a big weight will flatten us like a pancake and make people want to pour syrup onto us. Heavy Supports will cure that fear.
Increase starting strength with this lift. Bring the bar down controlled and rest it for a half-second without letting the bar sink. Accelerate with as much force and speed as possible.