Installing the Filter Frame:
1. Center the frame around the Display, being careful to not press on the Display.
The vertical centering is not critical, but I center the frame vertically in the face of the box, just for cosmetics.
The horizontal centering IS critical. Center the frame horizontally so that the Digit at either end of the display is equally visible. The frame is a "tight fit" horizontally.
2. Without moving the frame, carefully mark the box's plastic at the CENTER of each hole, using an awl or other sharp object. Do not press on the box "too much".
3. Remove the frame and CAREFULLY drill two 1/16 inch diameter holes, one centered at each awl mark. DO NOT drill more than about 1/8 inch into the box.
4. Mount the Frame with the two included screws, one into eack of the two carefully drilled 1/16" diameter holes. Do not press "too heavily" on the box while screwing in the screws.
5. Cut the thin plastic filter material (Red or Blue to match your Display's Digits) to just slide into the frame's recess. Better to cut too little off than too much.
6. Slide the filter into the "slot" at the top edge of the frame. If you have cut well, the filter will not fall out, but you will be able to slide the thin filter out if needed.