Hello All Pair of filters for bayonet style MSA half masks. I just opened them in hopes that they would fit my nem 3M mask. They do not. These P100 filters have a part number 815300, but it looks like they changed the part number and it is closest to this listing: https://www.amazon.com/dp/B001VXVU2C/ref=cm_sw_r_cp_apa_i_9TifFb4ZZ8QEV I'm looking for $15 for the set since they have been opened. Any takers? Daveanglero@gmail.com