A postal rate device for use in cooperation with a scale for facilitating interchangeability of an insert card bearing indicia representing a weight to rate conversion table. The device includes a cover which is configured with a recessed portion that accepts insertion of the insert card as well as a releasably securable shield. There are clips on the back side of the cover for removable attachment to the scale face plate. An aperture in the recessed portion of the cover facilitates effecting release of the shield by pushing a pencil or the like through the aperture even while the cover remains attached. Alternatively, once the cover is detached a pencil or the like may be pushed through an aperture to release the shield and insert card or the user may grasp the cover and push on the back side of the recessed portion to pop-out the shield and insert card. Accordingly, removal and replacement of the insert card from the scale, can be readily accomplished without the use of any special tools.