Perfect flexibility and rigidity High-quality polyester eyelet probe, with high-quality spring roller head, sufficient hardness, strong toughness, low friction and rapid tube penetration. Made of high quality galvanized steel, round and smooth ball, more durable than ordinary balls and not easy to fall. Package includes30m with 2 spring guide springs.Wire diameter 4mm Easy to UseLightweight, strong and smooth steel cable head on both heads can easily pass through twisted pipes.For access to wires and cables under floors, above ceilings, ducts and wall gaps. 360 Usable Straight] The headband on the end of the electrician's probe is 360 usable and easy to pass through the bend, unique connection method makes it durable and easy to use. Spring roller, easier to put in and faster than normal wire.