eyelet may also be designed without a split provided the eyelet of the subsequent bit rod member consist u2014 as is often the case u2014 of a material that is malleable allowing it to be split to begin with and then closed around the shank of the synthetic eyelet discussed here in any case the synthetic eyelet concerned is inserted with its shaft 146 or 166 respectively into a corresponding bore hole 150 or 170 respectively of the appropriate bit rod member 142 or 162 respectively while the shaft 146 and the bore hole 150 in the embodiment shown in fig8 are designed with matching threads 152 or 154 respectively the shaft 166 in fig9 designed with a number of circular grooves 172 arranged in succession and set at a distance from each other is cemented into the bore hole 170 of course cementing may also be used in the embodiment according to fig8 in any case a bit rod member fashioned in this manner will possess a traditional shape or one similar to that of member 6 in fig1 fig1 shows a two member bit rod 180 of a snaffle bit made essentially of synthetic or ceramic material where both members 182 and 184 feature inserts or platings 186 or 188 respectively made of different metals such as copper and zinc in this case too the horse 39 s saliva is capable of producing a potential difference between the two metals fig1 shows the central member of a bit rod.