Rail Joiners (Bullhead) Phosphor Bronze 4mm scale (100 Pack) Bullhead Fishplate 4mm scale 100 pcs pack: These high quality 4mm scale rail joiners have been made to look as realistic as possible and include bolt-head impressions along with minimal added metal therefore keeping the look of your trackwork as good as it can be. Phosphor bronze has minimal electrolytic reaction with nickel silver and stainless steel so they can be used as attachments for wiring. (useful as phosphor bronze is easy to solder too).