RBB Series rail brakes provide spring engaged/air released holding on profile guide rails (square rails) by clamping on the non bearing surfaces of the guide rail so has no impact on the guide rails performance. This brake can provide limited non-cyclic dynamic braking including E-stops. The unique design uses multiple redundant air/spring chambers to apply force on the rail through dual wedge and roller mechanisms, providing low backlash, accurate positioning and high reliability. This advanced design offers the highest performance guide rail holding solution and makes a great redundant braking solution to other types of braking systems especially in vertical applications. Nexen® Nexsafe™ Profile Guide Rail Brake, Spring Actuated Air Released, Series: RBB Series, 28.6 cc Air Volume, 6.9 bar Maximum, 33 to 150 °F, Nickel Plated, 127 mm L x 58 mm H Dimensions