RTI's Floating Base Socket Design:

What is a Floating Base Socket?
A floating base socket is a socket body with an additional spring loaded plane and recessed pogo pins. The name comes from the additional plane's ability to "float" independent of the socket body. They are typically used for BGA packages

How does the Floating Base Help?
The extra plane is also the pocket which holds the package. The floating pocket allows the package to line up by the balls rather than the edges, offering more precise alignment.

When are Floating Base sockets recommended?
A floating base socket is recommended for packages with wide tolerances in package size, and packages with fully populated arrays.

Does the Floating Base impact the socket footprint?
No, floating base sockets have the same footprint size and thickness as a comparable fixed base socket. However, the maximum package size is smaller.

Does the floating base impact the life span of the socket?
No, the durable springs and high quality manufacturing process yield a life span comparable to a "fixed base" design.