Thill® river floats are normally attached "top-and-bottom", or what we refer to as river style. Thill's quick-change silicone sleeves are threaded onto your line and then slipped over both the top and bottom of the Thill float, to "fix" the float in position when fishing in current.
In deeper stretches of slow-flowing rivers, you can use Thill center sliders. For deeper stretches of fast-flowing rivers, Thill offers a specialist float, the Thill® Gold Medal Double Ring Slider, that is fished as a slip float.