Park tool threadless star nut setter tns1the threadless nut setter is used to install star fangled nuts found on threadless headset systems thread the nut onto the tns insert into the fork stack and tap it in with a hammer sets the starfangled nut to 15mm and keeps it straight long handle helps prevent pinched fingers featuresthe tns 1 is for 1 and 1 18 headset systemsbuy park tool workshop tools from chain reaction cycles the worlds largest online bike store