This is one of my custom pens made from Paduk and curly maple and brass . It is a window type blank turned to very close tolerances with the curly maple showing through a window in the paduk . The outer paduk shell is less then 1/32" thick and curly maple inner shell is less then 1/32" thick over a 3/8" aluminum core . It uses a cigar transmission pressed into the aluminum core and the nib is threaded into the core so you can replace the parker refill .
