These are Philips woofers from the early ´70s model AD 8060/w8. Very good speakers, suitable for 7 to 10 lts in acoustic suspension systems. Surrounds are butyl rubber and they usually don´t deteriorate (the 49 is the week and 70 the year of manufacture). I´l post a pic of the big brother AD8065/w4 -4 ohms- ,larger magnet and more power handling.