Sometimes you have to assume your customer knows absolutely nothing about your craft, which is hard to do because you know it so well.
As someone who doesn't make jewelry or dog collars, I have no idea what makes your collars safe other than your guarantee that they are safe. I can't tell how they are constructed - I don't know if what is between (or under?) the beads is wire, or string, or plastic, or if they are glued together.
Probably many won't know what tensile strength means, either. Think about explaining it to a 10 year old.
I'd make several samples in some popular color schemes and make a listing for each one. Then I'd have one custom listing that says, pick your colors (and link to the custom listing in the other, static, listings).