white stuff on sliders

I notice on most of the professional sliders there is a white top. what is that?

PVC, It's a pipe made out of plastic; mostly used in construction for drainage, sprinklers for your lawn etc. you can buy it Home Depot.
It's super slippery when you hit it; so that's why they put that on the sliders. When plastic and wet plastic meet (your board) - it makes for a fun ride.
Google PVC and you will have a better idea of what it is. Hope it helped you out.

THe box type sliders are topped with HDPE (high density polyethelene) which is like the material that cutting boards are made out of but a little harder

I saw a slider with Ecoform (www.ecoform1.com) on the top. You can get it in 2"x8" boards 20 feet long. I'd like to try that out and see how it works.

I see a lot of sliders today made with some sort of composite decking. Trex is a popular one but there are many different brands available. If you see sliders at Radar Lake, Koppert, or Bow Lake they all use this product for the top layer. The 50/50 mix of wood and plastic will let the wakeboard slide but still give the rider control.

thanks because it always looked like the stuff they make cutting boards out of

Unfortunately, Trex and Fiberon are super expensive. Seems like there has to be something cheaper. I was surprised at how cheap the Ecoform is. I found a few other things in Home Depot that would probably work too and they were all cheaper than Trex. I know somebody that used that fake wood border stuff and it worked well.