The reel must be a fixed-spool reel which fits the size of the rod. A reel with a line capacity of about 200 metres of 0.20 mm braided line is perfect. Be aware that the reel must be able to withstand saltwater. Lately we have seen many new good reels which unfortunately cannot handle saltwater. The reel must be hardwearing. You cast and spin constantly when chasing sea trout. Many ball bearings in a reel is usually a good indication that it can handle wear.