Hi Hans, There are instances where the automatic scaling provided by \left and \right is not ideal and one has to use manual scaling. For example: \starttext \startTEXpage \startformula \left\langle \sum_{i=1}^n A_i x_i \right\rangle \hbox{ vs. } \bigg\langle \sum_{i=1}^n A_i x_i \bigg\rangle \stopformula \stopTEXpage \stoptext Currently, math fences always default to using \left and \right, which can lead to undesirable results. For example: \definemathfence [MEAN] [angle] [command=yes, color=blue] \starttext \startTEXpage \startformula \MEAN{ \sum_{i = 1}^n A_i x_i } \hbox{ vs. } \bigg\langle \sum_{i=1}^n A_i x_i \bigg\rangle \stopformula \stopTEXpage \stoptext Could we add an option to \definefence that allows the user to select the delimiter scaling using a key (say, `delimiter`) so that \MEAN[delimiter=auto] expands to \left\langle .. \right\langle \MEAN[delimiter=] expands to \langle .. \rangle \MEAN[delimiter=big] expands to \big\langle ... \big\rangle \MEAN[delimiter=Big] expands to \Big\langle ... \Big\rangle \MEAN[delimiter=bigg] expands to \bigg\langle ... \bigg\rangle \MEAN[delimiter=Bigg] expands to \Bigg\langle ... \Bigg\rangle I am not sure whether `delimiter` is the best key. I think that `scale` may be better, but using `scale` for specifying the scaling of math delimiters will be inconsistent with how `scale` is used everywhere else. Another option is to use `alternative` key. Thanks, Aditya