After I bought mine I tried putting the eraser end on the ripper end and was disappointed that it didn't fit. Maybe they don't want us poking ourselves with the ripper while using the rubber end. Someone told me she used tape to put hers on. "Only problem I have is with the top, you lay it down and poof, it goes under something and I can't find it and spend too much time looking for it. Wish it would fit on the other end while using the ripper."