No need to create a sticky mess using duct-tape to keep your Laser traveler blocks joined together. This Heat Shrink Tubing is long enough to seal the two blocks together and wide enough (1 inch inside diameter) to join the sister clips together before shrinking.
Just cut to length as needed, join blocks, and apply heat. The tubing will shrink up to 50 percent for a tight fit around the sister clips. We find a heat gun works best.