I agree kellyniro98 but these are pretty robust. If you get a chance to try one out I think you will be surprised. I have had one issue come to light since I have started using them more. The large frame Plastic articulator tends to have some very subtle vertical flex on multiple posterior units. The regular size unit is pretty rigid though. I have only needed the Larger size a few times but will most likely use brass on those types of cases for now on.