Having problems with the mark tube coming loose when using spring terminal blocks? Use a mark tube stopper to make it harder for the tube to drop out.[Features] - Secures mark tubes in general wiring applications. - Reduces mark tube drop out when crimp terminals are not used. (Is not fully fixed)[Specifications] - Material: Nylon 66 - Color: Natural - Compatible wire size: 0.3 to 0.5mm² / AWG22-20 (MS-3-050N) - Compatible wire size: 0.35 to 1.25mm² /AWG20-16 (MS-4-125N) - Compatible wire size: 1.25 to 3.5mm² / AWG16-10 (MS5-350N)