Pretty sturdy velcro straps, they don't dissolve as some other chinese products.
They are not practical though: if you lace 'em up the stupid way they'll fall off the cable. If you lace 'em up as intended, it's a complicated setup and they'll end up being to tightly clamped to the cable, won't be easy to move along the cable or to remove altogether, the clamp part will be a little too much bulgy.
So good construction, sturdy enough, very cheap, not totally well thought out do to do a perfect job.