No need for that clunky thing! 
Just get a few of these, in case you wanna build more rigs:
https://www.amazon.com/Warmstor-Desktop-Button-Computer-Switch/dp/B072FMVZJZ/ref=sr_1_1?s=electronics&ie=UTF8&qid=1503663102&sr=1-1-spons&keywords=pc+power+button&psc=1
Just get a few of these, in case you wanna build more rigs:
https://www.amazon.com/Warmstor-Desktop-Button-Computer-Switch/dp/B072FMVZJZ/ref=sr_1_1?s=electronics&ie=UTF8&qid=1503663102&sr=1-1-spons&keywords=pc+power+button&psc=1
Here you can buy it cheaper and also they have soldered LEDs
https://www.aliexpress.com/item/OOTDTY-New-PC-Desktop-Computer-Case-ATX-Power-On-Reset-Switch-Cable-With-HDD-LED-Light/32803394067.html