Barrel Lock Plunger Key | TTB-6Description Barrel Lock Plunger Key The Jonard Tools TTB 6 Barrel Lock Plunger Key is designed to unlock Channell LK03029817 and Highfield 93180775 S CATV barrel locks quickly and easily. It only works with these 2 types of locks with inside diameters from 0. 176" to 0. 196" (do not try to use for other purposes as it will not work). Features Features Made of high carbon alloy steel for heavy duty use and engineered for superior tamper resistance