Is the bumper on your Adult size Queen's Square Percussor as hard as a rock or has it melted away with time? That is the nature of rubber and some poly-materials. It is not the nature of this bumper that will remain springy and soft forever. It will hold its shape and fit nicely on a 1-1/2" size head, whether you buy our Queen's Square or our Rabiner-Babinski Percussors. It makes your hammer the best instrument in your bag.