Review on Upgrade Your Equipment With YXQ 5-Star Head Clamping Knob - M6X10 Thread, 25Mm Dia Base, Black Plastic (6Pcs) by Brad Knierim

I'm using these with 40mm based aluminum profile with 6mm T nuts and these are a fantastic way to allow for quick adjustment of an attachment. The 15mm length is perfect and the relatively large 25mm knob is easy to grab and turn and you can get it pretty tight. I've been using these with a flat washer to protect the plastic but you can use it without a washer and it still clamps down fairly tight.Good quality overall, I've never heard of the hardware company YXQ but as far as these knobs go, they seem to be very good quality and I'd recommend them. I'm sure there are many more uses than what I'm using them for, I've just been doing a lot with aluminum profile lately so that's what I used them on.