The main structural TETRIX pieces are aluminum channel with a trademarked hole pattern that enables connections at multiples of 45°. The pieces are attached using bolts. Other building elements include gears, wheels, motors and servos.
TETRIX can interface with the Lego Mindstorms NXT kit to allow the NXT intelligent brick to control TETRIX motors and servos. The connection is not just mechatronic, but also organizational: in the USA, LEGO Education North America is a joint venture between Pitsco, Inc. and the educational division of the LEGO Group.
FIRST Tech Challenge robots are built using the TETRIX building system and controlled by Lego Mindstorms NXT. For the 2011FIRST Robotics Competition season, the 'minibots' were constructed using TETRIX and other materials.