I just re-read your question. I was thinking about the fiberglass swim platform. But, you asked about the swim "ladder"...
That is a Garelick under platform swim ladder.
http://garelick.com/Under-Platform-Sliding-Ladder#
I got mine from amazon for $155 bucks. I like it a lot!
It's a little harder to put away, but I love having a 100% smooth swim platform surface with no ladder parts in my way.
Kevin