The Crescent Model A Articulator from Crescent/Rinn Dental Mfg. is used for partials and features a center spring with adjustable tension. The upper and lower sections of the articulator can be taken apart and put back together quickly without any hassle. This articulator contains a center bar in the upper and lower bow that gives the articulator added strength and maximum plaster retention. It has an open construction that allows for easy access to all surfaces.