Nelco Ultra 5102A Free Arm rear arm mounted twin spool pin holder with mounting screw.  Nice clean shape.  Screw base with nut & washered twin pins stand straight up (not backward leaning).  Holder has center screw with small bump to right for securing to second hole in back arm of machine.  May work on other free arm machines and other Nelco models.  $3 shipping to lower 48.