that's not a joplin clamp - similar looking maybe but not the same. The remote lever is different, the remote cable attaches to the post in a different location, and the ring at the main seal is different. Seems like a lot of differences for the same post.
If anyone is after a joplin CRC has them very cheap at the moment.
I would however recommend spending a bit more and going to Superstar components as the service is AMAZING.
I had a problem with my seat post on Thursday, I e-mailed superstar at 7pm saying that it was a shame as going biking this weekend. Got an e-mail back at 9pm saying it is sorted.
Someone arrived at my house 3pm friday with the newest upgraded model and to collect the faulty one. I can't imagine how he got a same day courier to travel half the length of the country in a matter of hours, but I am impressed.
Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?