I usually just use the old seal to push the new one in! Guess that's not possible with rope...
The 250 seals do come with a specially shaped piece of plastic so that you don't damage the BACK of the seal when inserting it.
I always use stuff like that because you know if they spent the extra $.03 to include it, it must be because the had to replace a million seals for being faulty...
-Boyo
