Not the ideal solution here: if you can't find any try looking for the headset top cushion replacement. Not as big but you can use two together. In case they aren't sticky use a double face tape

Like this one: https://www.amazon.com/dp/B00P1RQTJS/ref=cm_sw_r_cp_apa_glt_fabc_E2XMC96XCFT9P6NWAVQJ?_encoding=UTF8&psc=1