This is a Melzi Board holder, to move the board further out to gain Z Hight on the Huxley RepRap.

A Melzi Board is a compact all-in-one controller board for RepRaps with one extruder head, optimized for mass production.

The point of RepRap is to make itself. But sometimes people just want plug-and-play RepRap electronics so they can concentrate on the other aspects of the machine, or just because they are more software or mechanics oriented than electronics oriented.

Melzi is designed to be a complete set of RepRap electronics that should be very cheap to mass produce. 

RepRap is humanity's first general-purpose self-replicating manufacturing machine.

RepRap takes the form of a free desktop 3D printer capable of printing plastic objects. Since many parts of RepRap are made from plastic and RepRap prints those parts, RepRap self-replicates by making a kit of itself - a kit that anyone can assemble given time and materials. It also means that - if you've got a RepRap - you can print lots of useful stuff, and you can print another RepRap for a friend..

RepRap Version III "Huxley" is being developed. It is based on Ed's original Mini-Mendel design, together with a lot of work already put in by ErikDeBruijn and others. Huxley is named, like all RepRaps, after a biologist: Thomas Henry Hux.