Neutrik company manufacturing very good products and these plugs are awesome, they're not cheap, if you compare to other non-branded or another brands plugs, the craftmanship is very accurate and the materials from who they've been made is very high grade. i recommend these plugs and other from this company for those, who wants very high quality :) .
P.S.: these plugs have instructions on their website, how to prepare for soldering :), briliant!