Orbital shakers are used for everything from gentle mixes and washes, to more vigorous agitation.
The original distinction between an orbital shaker and laboratory rocker was the angle of motion. Orbital shakers would simply rotate in a circle while rockers were inclined at an angle and offer a more gentle washing and mixing motion.
One can now find orbital shakers that move through a 3D range of motion, often called nutating shakers.
When shopping for the perfect orbital shaker (need a laboratory rocker? Look over here) things to consider are:
The size of the orbital shaker platform and whether it can be increased with a stacking unit
The speed range of the orbital shaker, and whether it is set (fixed) or adjustable
The tilt angle, and whether that is set or adjustable
In general, low speed orbital shakers are the right fit for washing and de-staining activities associated with blotting. These allow for some speed control with a max rpm rate of 70-80.
Labs that work with bacterial and yeast cultures typically need a shaker than can top out at 300 rpm.
All of our laboratory shakers and rockers are designed to perform well in the cold room, which increases their range of use.