This silicone rubber mould has been developed in collaboration with Cancer Research UK's London laboratories. The mould is designed to aid orientation and trimming of the sample. It produces a block which is easy to mount in the SEM for correct orientation of the block face with respect to the ion and electron beams. During FIB milling, re-deposition of sputtered material back onto the block face is minimised by positioning the sample in an overhang of resin. This four-cavity mould can be reused many times if handled with care.