Hellermanntyton fixing elements for corrugated tubing with fir tree ctc range hellermann tyton 151 00018 the hellermanntyton 151 00018 ctc10ft6lg is a clamp for corrugated conduit tubing with a base in the shape of a fir tree from the ctc series due to the individual fins the clamp can be easily inserted into a pre drilled hole the corrugated conduit is then snapped into the clamp where it is securely held the rib on the inside of the clamp fits into the profile of the tubing and pre