Thumb Score: +1

Lee Valley Clearance — These are the Ernst Socket Boss (unbranded online, but they shipped in Ernst OEM packaging).

Made in the USA, removable rails, quarter-turn twist lock, universal design (you can mix and match drive sizes). From personal experience, I can vouch that these are absolutely fantastic in terms of usability — really well thought-out. If I have a negative, all the parts are plastic — but I haven’t broken any yet, and replacement pegs are widely available. This appears to be rebranded to other OEMs, such as Tekton.