40 compatibility; I was not sure; could not figure out if these can fit as replacement earpads, but I had to try anyway as stock HD 4. Its a croppers dream lens. To me, it was obvious. Still bad product. Ive only worn them a few times and the both parts of foot covering of the slider have started to come unstuck. This is my first record player. If you have never worked with spray foam. Quello che non è scritto sta nel fatto che è composto di due pezzi per cui alla prima slabbratura e deformazione inevitabile i pezzi potranno essere molto probabilmente persi perchè non collegati fra loro. But size is just the start of the problems. Worth the cash.