Device with disposable element

A body 102 has a hole 190 and retaining pockets 180 including a staking post 182 and a reference surface 184. A PCB 120 has contactors 124 with flanges 128 which extend beyond the edge of the PCB - these contact the reference surface with the staking posts going through holes 128a. The body may then be deformed to hold the PCB in place, see Fig 11B. Alternatively, a body (310, Fig 13A) has an upper section (310a) and a lower section (310b) joined by a flexible arm (310c). The upper section has an opening (313) and a printed film (330) has electrodes (350a, b, Fig 13B) which are exposed through this opening. The film folds back on itself to wrap around a compressible spring element (320). The PCB may be used as a detachable and disposable medical sensor. Cantilever contacts (126, Fig 2) may connect it to a reusable counterpart, and these contacts may slide across planar counterpart contacts (160a, b, c, Fig 3) during connection.