from buffalo ny: don't get "trapped" by the letters, the common P trap
has both removable nuts. other less common J trap has a captive nut
[where the short side of the trap has its own nut that screws upward
onto the threaded wall arm]. there are many varieties of traps in
plumbing but mostly just replace the kitchen with 1-1/2" and the
bathroom sink with 1-1/4" often found as a combination sized trap with
extra insert adapter in the bag for the smaller sink size.

i agree with the lack of photos.