A horizontal frame is mounted on a rod fitted to a base & carries a steel wire stretched across it, the tension of which can be adjusted by a tightening screw. A light weight metal pointer with a counterpoise is attached to the centre of the wire by a clamp. A pan is hung from a notch in the pointer and has a hook at its underside from which can be suspended a light weight rectangular frame or a metal clip to hold a microslide edge. The tip of the pointer moves over a graduated scale. With rectangular wire frame, slide clip, six microslides & 3 metres of spare wire.