The 1947 - 1948 original TS-4 to the early production TS-4F chassis' used a rectangular cover. The rounded cover will not fit the 1947 - 1948 original TS-4 to the early production TS-4F chassis '. Therectangular cover will fit and work on all the TS-4 chassis and the TS-18 chassis buttherounded covers ones will only fit the later chassis as stated in bold lettering above.
