Beginner's Guide to Buying a Kneeboard Tow Rope
Source: Action Sports International (http://www.actionsportsinternational.com)
This article is aimed at the novice Kneeboarder as it is assumed that an intermediate or advanced rider will probably know most of this stuff already.
Recreational / beginner kneeboards often have what is known as a Hydro Hook (a.k.a. Aquatic Hook). This is a simple plastic flip-up hook (or plastic block) attached to the nose of the board to enable the tow handle to be attached to it and take all the load during deep water starts. The handle is simply placed behind the hook, which then takes all of the load off the rider when the tow vehicle powers up. Once up to speed and composed, the rider can then pull the handle toward them, which detatches it and gives them full control.
To be honest, you can use more or less any wake or ski rope to go kneeboarding with, but purpose made kneeboarding tow ropes are available which work well with the Hydro Hook. As you progress, also consider using a 15" wake handle rather than the narrower 12" ski handle as this makes it easier to perform tricks where the rope is passed behind your back.