Fits Big Twin 1970-1984 with square type oil tank, FXR 1984-1994, FLT 1987-1992, Sportster 1970-1978 and many custom oil tanks. Probe length is 4 inches.Fits Big Twin 1970-1984 with square type oil tank, FXR 1984-1994, FLT 1987-1992, Sportster 1970-1978 and many custom oil tanks. Probe length is 4 inches. Fits into oil cap in place of stock cap. Temperature gauge surrounded by very good chrome.