I find that a salad spinner is a necessity in my kitchen.

For one thing it saves oodles of time and also helps to preserve my salad ingredients while they are waiting in the fridge. Wash and spin. It's a simple as that!

Basically salad spinners are all similar in design.

A basket that is perforated, sits in a larger outer bowl, and simple gears linked to a mechanism located in the lid spin the perforated basket very quickly.

The centrifugal force of spinning splays the greens onto the sides of the basket and squeezes the water through the holes in the basket and then into the larger, outer bowl.

Aside from this fundamental design, there are two important variables.

1. the lid: there's a hole in the lid on some models so that water can proceed directly into the basket as you spin. On alternate models, the lid has to be removed to wash the veggies, so the washing and spinning events are not simultaneous but sequential.
   
2. the outer bowl: the basic design depends upon a solid outer bowl that catches and holds water. The exterior bowl on some salad spinners is perforated so the liquid can flow right through.

The salad spinner is, for all us salad-enthusiasts, the most wonderful and useful invention and one great brand known as the 'Oxo' spinner is especially well-designed for us 'spinners'. 

Known for some time as a company who were great at creating everything from tea kettles to garlic presses to silicone pot grips,Oxo, an American firm has also moved into the salad spinner market. They removed the old string pull and crank arm, and replaced them with a pump-action  device.

You just push a button, and the pump springs up. Now you  get it spinning fast with some simple pumping-action  and then push the brakes (a button) to stop the spinning almost immediately. 

Also Oxo this salad spinner design has a  useful detail in a rim of sticky rubber circling  the bottom of the bowl to make it 'stay put' while you pump. 

The plastic itself is  non-porous hence it is largely ordour resistant.