.. along w a non marring wrench... Turned out my ace rb kit had a 1/8" Allen for the lock screw, so thought bummer, didn't need this afterall..!! ????BUT... Then i decided bc my deltas use the same #70 builder special balls that i would go to my ace and get another 12 buck rb kit and tackle the just as leaky bathroom sink.. THATS WHERE I NEEDED THIS TOOL.. ( and it turns out, the other one also ,so you might wanna have one of those..!) (Also reviewed bc i bought them at the same time so its in my reviews if you click on my name).. Why is that?, vid i watched didnt.. ..theirs came right off, ....well bc mine had 15 yrs of hard water!!! So whats supposed to happen is .. When you use this perfect lil tool in the holes in the white ring, the silver part gently unscrews with it...Unless its locked on w crud????♀️.. Mine, instead ,gently unscrewed itself right outa the silver that was supposed to go w it.. ..where luckily i had my other tool..took that, 20 min and an act of God, but it came free.. SO .. my advice to newbies.. It IS EASY AND CHEAP.. but you really do need the right tools or you will likely break damage the faucet, yourself, your ego, your sanity.. I used a pumice to carefully ( it can scratch) Remove calcium off of the parts i took off,.washed rinsed, wiped dry w a clean lint free rag.. Dont mess w in the hole , just dab out water, i was told you can loosen crud n get it jammed in the holes.. I Did use my plumber grease ( also bought here) as my kitchen vid had showed... On bttm of ball, underside of part that sits on it, as well as area handle rotates but not near screw( dont want that wigglin free) In the end, i lightly screwed white part back into silver part... then hand screwed the whole assembly, then used this tool to tighten the white part in, where it grabbed the silver and ( bc now all were clean,) It tightened as it was supposed to.. PERFECT LIL TOOL, WILL USE AGAIN ON OTHERS AS OUR WHOLE HOUSE IS DELTA LEVERS .. do yourself a favour and get the other tool and the grease... I think attempting to use another tool in this plastic will just jack it up..same w the smooth wrench, its slender n smooth so it fits the shallow grooves.. Hope this helps someone???? ????????????????????