Connecting bars for the mini system are 3.2mm stainless steel. The Small system has Carbon Fibre and Titanium 6.3mm connecting bars, and the Large system has 9.5mm carbon fibre and aluminium connecting bars. Carbon Fibre is radiolucent meaning that the connecting bar does not obscure the image when a radiograph is taken. Considering bending strength, Titanium is stiffer than Carbon Fibre which in turn is stiffer than Aluminium.
As for all linear ESF systems, the size of system chosen is chosen by measuring the size of the bone to be fixed. The craniocaudal and mediolateral dimensions of the bone are measured at the point of intended ESF pin application, and an ESF pin that has a shank diameter approximately 25% the narrowest dimension of the bone is chosen. When the size of ESF pins has been determined, the size of ESF clamp that will accomodate such ESF pins is determined, and therefore the size of connecting bar that is compatible with the clamp. As a generalisation, the mini system is suitable for cats and small dogs, the small for medium sized dogs, and the large for larger dogs.